Note: Descriptions are shown in the official language in which they were submitted.
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SYS [EMS AND METHODS FOR BEACON DETECTION INFRASTRUCTURES
BACKGROUND
[0002] The field of the disclosure relates generally to satellite service
transmission systems, and particularly to management of fixed satellite
service protection
using real-time measurements.
[0003] Conventional fixed satellite service (FSS) earth stations, or sites,
operate across a variety of spectrum bands for Geostationary Earth Orbit (GEO)
satellites.
The citizens band radio service (CBRS), defined by the FCC for fixed wireless
and mobile
communications operates in the 3550-3700 MHz (3.55-3.7 GHz) band and use of
this
spectrum is authorized and managed by a Spectrum Access System (SAS). The
function
of the SAS is to maintain a database of all transmitters that use the CBRS
band, including
the transmitter locations and transmitter powers. The SAS uses a propagation
model to
determine interference between each FSS site and radio access points (AP) to
ensure
globally across the totality of its management area that the interference is
below an
acceptable interference threshold at each location. The SAS uses frequency
planning
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algorithms known in the field of cellular communications for Frequency
Division Multiple
Access (FDMA), such as GSM. Thus, the SAS is able to allocate to each AP or
citizens
broadband radio service device (CBSD), the frequency of operation, bandwidth,
and
transmitter power.
[0004] The C-band, which is designated by the IEEE and used for satellite
communications, covers the 3-8 GHz band. The FSS incumbents in the 3.7-4.2 GHz
of
downlink C-band are identical in nature and technology to the FSS incumbents
within the
3.55-3.7 CBRS band, and these incumbents are provided co-channel and
adjacent-
channel protection (out of band) under the Part 96 rules of the United States
Federal
Communications Commission (FCC). FSS incumbents within the CBRS band use 3.665
to
3.7 GHz. Additionally, there is a requirement to limit the amount of aggregate
interference
across the entire downlink band to avoid gain compression at the Low Noise
Amplifier
(LNA) used for satellite signal reception. The CBRS band is considered fairly
manageable
at present due to the relatively small number of FSS sites (<100). In
contrast, the 3.7-4.2
GHz band presently includes over 4700 registered FSS sites, and may include as
many or
more unregistered FSS sites.
[0005] There are approximately, at this time, 160 geostationary satellites
utilizing the C-band for downlink in the 3.7-4.2 MHz spectrum. Each satellite
typically
employs 24 transponders, each with a 36 MHz signal bandwidth. Carrier spacing
is 40
MHz, 2 x 500 MHz used on each satellite, and 12 carriers each for horizontal
and vertical
polarization. The carrier-to-noise (C/N) margins are typically 2-4 dB. The
earth stations
typically employ multiple satellite dishes and frequency agile receivers to
decode specific
video/data streams off individual transponders. The actual received bandwidth
at the FSS
sites varies. Multiple dish antennas are often used to obtain programming from
multiple
satellites. The United States C-band frequency chart is shown below (in GHz)
in Table 1.
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TABLE 1 (Frequencies in GHz)
Horizontal Horizontal Channel Vertical Vertical
Uplink Downlink Downlink Uplink
3.720 1 5.945
5.965 2 3.740
3.760 3 5.985
6.005 4 3.780
3.800 5 6.025
6.045 6 3.820
3.840 7 6.065
6.085 8 3.860
3.880 9 6.105
6.125 10 3.900
3.920 11 6.145
6.165 12 3.940
3.960 13 6.185
6.205 14 3.980
4.000 15 6.225
6.245 16 4.020
4.040 17 6.265
6.285 18 4.060
4.080 19 6.305
6.325 20 4.100
4.120 21 6.345
6.365 22 4.140
4.160 23 6.385
6.405 24 4.180
[0006] The C-band downlink spectrum includes 500 MHz adjacent to the
CBRS band, but sharing this adjacent spectrum with mobile and fixed wireless
usage has
been problematic for technological reasons, and according to the existing
protection rules,
which are highly conservative in nature. Satellite receivers, for example, are
extremely
sensitive, having an interference threshold of -129 dBm/MHz according to the
requirement
from FCC Part 96, and operate below the thermal noise level of the actual band
itself, often
working with effective thermal noise of 80K, with high gain antennas
(satellite dishes) to
amplify a weak satellite signal before detection. Relatively small power
transmitters
sharing the same band may cause interference over distances of tens of
kilometers or
greater.
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[0007] There is no system currently in place to monitor and report
operating parameters, such as the actual frequency channel usage or the
direction and
elevation of reception of the satellite dish with its dish size (which
determines its gain for
satellite reception) at each FSS site. Accordingly, the protection rules are
conservative
because existing SAS schemes have no capability to remedy FSS interference.
Furthermore, no conventional propagation models accurately predict the
transmission loss
between the transmitter and the receiver, or to the FSS site from the point of
interference,
which further encourages over protection of FSS sites from wireless
transmitters that
occupy the same band. Additionally, building construction/demolition, as
well
atmospheric effects, including change from one season to another, can cause
unpredictable
propagation behavior, and FSS site operators may frequently change the FSS
site operating
parameters, which encourages the operators to register their respective FSS
sites for full arc
and full bandwidth protection when, in practice, the actual use may be much
more
restricted.
[0008] FIG. 1 is a schematic illustration of a conventional satellite service
protection scheme 100 for an FSS site 102. FSS site 102 includes at least one
earth satellite
ground station 104, or earth station 104, which generally includes a dish and
a frequency
agile receiver (not separately numbered), for receiving and decoding
video/data streams
from satellite 106 (e.g., GEO C-band satellite). Protection scheme 100 further
includes a
CBSD 108, which may be a base station in the cellular context, such as an
eNodeB for
LTE, mounted on a vertical support or tower 110. CBSD 108 may be a radio
access point
(AP) used for fixed wireless access. Authorization and resource allocation of
CB SD 108 is
governed by an SAS 112, which is in operable communication with CBSD 108 over
a data
link 114 (e.g., wireless or wired Internet connection, etc.).
[0009] In operation of protection scheme 100, CBSD 108 requests
authorization and resource allocation from SAS 112. SAS 112 has knowledge of
the
operating parameters of FSS site 102, which are communicated over a reporting
link 115.
Initially, the resource allocation to CBSD 108 can be provided using a
propagation model
to avoid interference. This interference modeling can model co-channel,
adjacent channel,
second adjacent channel, and aggregate band interference. In this example, SAS
112 may
use a frequency planning algorithm that is similar to a model used for
cellular networks to
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determine the allocation of both the channel frequency and power. However,
this modeling
technique is not aware of the actual loss between CBSD 108 and FSS site 102,
which may
influenced by obstructions 116 (buildings, elevated ground, seasonal effects,
foliage, etc.)
along an actual transmission path 118 therebetween. SAS 112 therefore
implements
protection scheme 100 according to an estimate model that utilizes a mapped
distance 120
between CBSD 108 and FSS site 102 to predict a pass loss estimate.
[0010] However, because SAS 112 cannot measure the actual loss along
the actual transmission path 118, the path loss estimate will be inaccurate,
and typically
based on the worst-case scenario. Such inaccuracies therefore generally
encourage over
protection of the FSS sites and results in limited CBRS spectrum utilization,
as well as the
C-band downlink spectrum overall, Accordingly, it would be desirable to
develop an FSS
protection scheme that can determine actual path loss considerations in real
time to
maximize use of available spectra, but without impairing the protection to the
sensitive
satellite receivers.
[0011] FIG. 2 is a schematic illustration of a conventional satellite service
protection system 200 implementing protection scheme 100, FIG. 1, for earth
station 104
receiving a video/data stream 202 from satellite 106. In this example, stream
202 has a
total transmit spectrum of 500 MI-lz between 3700 MHz and 4200 MHz, that is,
500 MI-lz
of the GEO C-band satellite downlink spectrum adjacent to the CBRS band. Under
the
current government rules, protection scheme 100 implements the FCC Part 96
protection
scheme for 3600-3700 MHz earth stations. System 200 includes a low-noise block
(LNB)
204 and a headend 206. LNB 204 includes, for example, a feed horn 208, a
bandpass filter
210, and an LNA/downconverter 212. An FCC reference point (not shown), for
interference calculations by the SAS, is generally taken between bandpass
filter 210 and
LNA 212. Headend 206 includes a plurality of channel receivers 214.
[0012] In operation of system 200, LNB 204 functions as the receiving
device for the dish of earth station 104, collecting from the dish the
amplified received
radio waves as a block of frequency sub-blocks a through 1 (e.g., 12 x 40 MHz
channels,
see Table 1, above). LNB 204 amplifies and downconverts the collected block
into a lower
block of intermediate frequencies (IF) (e.g., 950-1450 MHz), which are then
distributed as
individual sub-blocks (c, f, b, i in this example) along a receiver signal
distribution chain
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216 to respective channel receivers 214, which are typically contained in a
distribution rack
in headend 206.
[0013] In this example, earth station 104 utilizes a 2-meter antenna, with
protection of FSS LNB from gain compression of -60 dBm aggregate LNB input
signal
level from all terrestrial radio emissions within 40 km radius of the FSS
across the 500
MHz band. Protection of FSS receiver noise floor is -129 dBm/MHz, as discussed
above,
from all co-channel terrestrial radio signals within 150 km radius of the FSS,
based on
maximum noise equal to -10 dB I/N, for 0.25 dB max noise rise at measurement
point. It
should be noted, that since many FSS sites use the 3.7-4.2 GHz band across the
United
States, such protection areas of 40km and 150km radius frequently overlap each
other, and
thus the protection criteria to address interference for each radio access
point sharing this
band must be satisfied at each FSS site within the vicinity.
[0014] FCC rules also specify the acceptable levels of adjacent channel
interference in the first and second adjacent channels, e.g., which allow 40
and 52 dB
higher signal strengths, respectively, for the first and second adjacent
channels due to their
increased frequency separation from the central channel, to that used for
signal reception.
Accordingly, the re-use of unused channels is optimally based initially upon
the second
adjacent channel before the first adjacent channel in an optimization strategy
for optimum
interference management. The FCC Rules also specify standard FSS dish gain
profile (H
and V planes) and also band pass filter attenuation. The antenna pattern (not
shown) output
from the dish is highly directional, the Half Power Beamwidth (HPBW) is
approximately
1.3 degrees, and the antenna gain is 36.5dBI for a 2m diameter dish with an
efficiency of
65%.
[0015] Conventionally, not all of the twelve 40 MHz channels (a through
1) over one polarization (see Table 1, above) are actually demodulated along
distribution
chain 216 for a given FSS site (e.g., FSS site 102, FIG. 1, having 1-N earth
stations 104).
In the example illustrated in FIG. 2, only a third of the twelve polarization
channels (that is,
24 channels in total, but only twelve for each of the two polarizations), are
demodulated at
headend 206, with protection scheme 100 requiring co-channel protection of an
"unused"
portion 218 of the transmit spectrum unavailable for use by other CBSDs 220
(or Radio
Access Points (RAPs)) seeking authorization and resource allocation from SAS
112 for
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FSS site 102. That is, in this example, unused portion 218 represents 320 MHz
of available
terrestrial spectrum that is wasted and unusable under protection scheme 100.
Additionally, in consideration of other FSS sites in the vicinity of a
particular CBSD/RAP
220 that may utilize different satellite down-link channels, there will be
further constraints
on the spectrum availability. In areas of high FSS site density, the whole of
the 500MHz
of spectrum will become unavailable to the particular RAP.
[0016] FIGS. 3A-3B illustrate data tables 300, 302 for loss and separation
distances according to the conventional protection scheme 100, FIG. 1, and
system 200,
FIG. 2. Tables 300 and 302 are each illustrated with respect to co-channel,
LNB blocking,
first adjacent out-of-band emission (00BE) and second adjacent 00BE for a
single
interfering transmitter. In consideration of the loss values taken from table
300, minimum
separation distances to reduce interference below the various thresholds in
table 302 are
determined using a free space path loss (FSL) equation and two common
propagations
models used for cellular communications: Cost 231 Hata (231 Hata), Cost 231
Walfish-
Ikegami (231 WI). These tables illustrate the significant variations in
associated protection
distances depending on the model choice. For example, for an Azimuth of 0
degrees, a
satellite dish elevation of 5 degrees and a satellite gain of 14.5 dB, the
predicted separation
distance is 6940 km for FSL, 7.4 km for 231 WI and 3.4 km for 231 Hata.
[0017] Use of the most conservative model, FSL, will result in massive
over protection of the FSS and under-utilization of the spectrum. In the
example
illustrated, the dish size is 2 m, antenna height of FSS is 4m, and small cell
height is 1.5 m
for both 231 WI and 231 Hata. As can be seen from these examples, the FSL
calculation is
not able to take into account actual terrain/obstacle considerations; the FSL
calculation
does use assumptions on antenna height. Even the use of other models such as
231 Hata
and 231 WL require the choice of parameters that reflect different terrains
profiles and
even these can produce significant variations within themselves based on that
choice.
Furthermore, because such empirical models only produce a prediction of the
average loss
between two points in space, in practice, the actual loss between these two
points may
significantly depend on many other factors including the terrain therebetween.
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BRiFF SUMMARY
[0018] In an aspect, a system is provided for protecting a fixed satellite
service site. The system includes at least one earth station, a first beacon
detector disposed
within close proximity to the at least one earth station, a central server in
operable
communication with the fixed satellite service site and the first beacon
detector, an access
point configured to request authorization from the central server for resource
allocation,
and a beacon transmitter disposed within close proximity to the access point.
The beacon
transmitter is configured to transmit a beacon signal to one or more of the
central server
and the first beacon detector, and the beacon signal uniquely identifies the
access point.
[0019] In another aspect, a communication system includes an earth
station configured to receive a downlink transmission from a satellite and
transmit an
uplink transmission to the satellite. The communication system further
includes a server in
operable communication with the earth station, a beacon detector in operable
communication with the server, an access point configured to operate within a
proximity of
the earth station, and a beacon transmitter disposed within close proximity to
the access
point. The beacon transmitter is configured to transmit a beacon signal to one
or more of
the server and the beacon detector. The beacon signal uniquely identifies the
access point.
The server is configured to implement a measurement-based protection scheme
with
respect to at least one of the downlink transmission and the uplink
transmission.
BRIFF DESCRIPTION OF THE DRAWINGS
[0020] These and other features, aspects, and advantages of the present
disclosure will become better understood when the following detailed
description is read
with reference to the accompanying drawings in which like characters represent
like parts
throughout the drawings, wherein:
[0021] FIG. 1 is a schematic illustration of a conventional satellite service
protection scheme according to an estimate model.
[0022] FIG. 2 is a schematic illustration of a conventional satellite service
protection system implementing the scheme depicted in FIG. 1.
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[0023] FIGS. 3A-3B illustrate data tables for gain and separation distances
according to the conventional protection scheme depicted in FIG. 1 and system
depicted in
FIG. 2.
[0024] FIG. 4 is a schematic illustration of a satellite service protection
scheme, according to an embodiment.
[0025] FIG. 5 is a schematic illustration of a satellite service protection
system implementing the scheme depicted in FIG. 4, according to an embodiment.
[0026] FIG. 6 is a flow diagram for an exemplary process for operating
the satellite service protection system depicted in FIG. 5, according to an
embodiment.
[0027] FIG. 7 is a graphical illustration depicting a comparison of
conventional fixed point-to-point distributions for the 4 GHz band and the
Lower 6 GHz
band.
[0028] FIG. 8A is a graphical illustration depicting a conventional earth
station location distribution for the 4 GHz downlink band.
[0029] FIG. 8B is a graphical illustration depicting a conventional plot
comparison of fixed microwave earth station distribution trends for the 6 GHz
uplink band
and the 4 GHz downlink band.
[0030] FIG. 9 is a graphical illustration of a chart depicting relative
percentages of existing earth station database problems conventionally
encountered.
[0031] FIG. 10 is a schematic illustration of a shared use system,
according to an embodiment.
[0032] FIG. 11A depicts an exemplary protection zone layering scheme,
according to an embodiment.
[0033] FIG. 11B illustrates a data table for calculating respective
parameters of area zones according to protection zone layering scheme depicted
in FIG.
11A.
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[0034] FIG. 12 is a schematic illustrations of a shared use system within
the exclusion zone depicted in FIG. 11A, according to an embodiment.
[0035] FIG. 12A illustrates a multi-zone operational distribution of UEs
around the FSS site depicted in FIG. 11A, according to an embodiment.
[0036] FIG. 12B is an overhead view of a partial schematic illustration of
a corner effect, according to an embodiment.
[0037] FIG. 12C is a partial schematic illustration of a hotspot effect,
according to an embodiment.
[0038] FIG. 13 is a schematic illustration of a shared use system that
implements a measurement-based protection scheme for a self-calibrating
propagation
model, according to an embodiment.
[0039] FIG. 14 is a graphical illustration depicting comparative data plots
of single-slope and dual-slope models for high density commercial morphology-
per-clutter
classifications, according to an embodiment.
[0040] FIG. 15 is a graphical illustration depicting a plot of an addressable
population with respect to a radius of an exclusion zone, according to an
embodiment.
[0041] FIGS. 16A-16B illustrate data tables for satellite protection
maximum path loss with respect to a single access point, and 800 access
points,
respectively, within the satellite beam width, according to an embodiment.
[0042] FIG. 17 illustrates a patterned grid region including a plurality of
contiguous grid blocks, according to an embodiment.
[0043] FIG. 18 is a graphical illustration depicting comparative data plots
1802 of dual-slope propagation models, according to an embodiment.
[0044] FIG. 19 is a schematic illustration of a fixed satellite service site
configured to implement the protection scheme depicted in FIG. 4, according to
an
embodiment.
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[0045] FIG. 20 is a schematic illustration of a beacon detection system
implementing the earth station and the platform-mounted beacon receiver
depicted in FIG.
19, according to an embodiment.
[0046] FIG. 21 is a schematic illustration of a beacon detection system
implementing the earth station and the integrated beacon receiver depicted in
FIG. 19,
according to an embodiment.
[0047] FIG. 22 is a schematic illustration of a distributed antenna system
configured to implement the protection scheme depicted in FIG. 4, according to
an
embodiment.
[0048] FIG. 23 is a schematic illustration of a multiple-antenna shared-use
system, according to an embodiment.
[0049] FIG. 24 illustrates a far field beam pattern for a multiple antenna
system, according to an embodiment.
[0050] FIG. 25 is a schematic illustration of a multiple antenna system,
according to an embodiment.
[0051] FIG. 26 is a schematic illustration of a multiple antenna system,
according to an embodiment.
[0052] FIG. 27 is a schematic illustration of a multiple antenna system,
according to an embodiment.
[0053] FIG. 28 is a schematic illustration of a multiple antenna system,
according to an embodiment.
[0054] FIG. 29 is a schematic illustration of multiple antenna system,
according to an embodiment.
[0055] FIG. 30 is a schematic illustration of a multiple antenna system,
according to an embodiment.
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[0056] FIG. 31 is a schematic illustration of a mobile network
implementing joint beamforming and null forming, according to an embodiment.
[0057] FIGS. 32A-C are schematic illustrations of a mobile network
configured to implement dynamic null forming for different respective
frequencies,
according to an embodiment.
[0058] FIG. 33 is a schematic illustration of a mobile network
implementing channel estimation, according to an embodiment.
[0059] FIG. 34 is a schematic illustration of a mobile network
implementing satellite system information relay, according to an embodiment.
[0060] FIG. 35 is a flow diagram of an exemplary process for operating a
multiple antenna system, according to an embodiment.
[0061] FIG. 36 is a schematic illustration of a multiple antenna system
implementing a directional antenna subsystem for satellite downlink
protection, according
to an embodiment.
[0062] FIG. 37A is a schematic illustration of a mobile network
implementing directional coverage implementing the directional antenna
depicted in FIG.
36.
[0063] FIG. 37B is a schematic illustration of a mobile network
implementing a conventional omni-directional antenna.
[0064] FIG. 38 is a schematic illustration of a communication system,
according to an embodiment.
[0065] Unless otherwise indicated, the drawings provided herein are
meant to illustrate features of embodiments of this disclosure. These features
are believed
to be applicable in a wide variety of systems including one or more
embodiments of this
disclosure. As such, the drawings are not meant to include all conventional
features known
by those of ordinary skill in the art to be required for the practice of the
embodiments
disclosed herein.
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DETAILED DESCRIPTION
[0066] In the following specification and claims, reference will be made to
a number of terms, which shall be defined to have the following meanings.
[0067] The singular forms "a," "an," and "the" include plural references
unless the context clearly dictates otherwise.
[0068] "Optional" or "optionally" means that the subsequently described
event or circumstance may or may not occur, and that the description includes
instances
where the event occurs and instances where it does not.
[0069] As used herein, the term "database" may refer to either a body of
data, a relational database management system (RDBMS), or to both, and may
include a
collection of data including hierarchical databases, relational databases,
flat file databases,
object-relational databases, object oriented databases, and/or another
structured collection
of records or data that is stored in a computer system.
[0070] Furthermore, as used herein, the term "real-time" refers to at least
one of the time of occurrence of the associated events, the time of
measurement and
collection of predetermined data, the time for a computing device (e.g., a
processor) to
process the data, and the time of a system response to the events and the
environment. In
the embodiments described herein, these activities and events occur
substantially
instantaneously.
[0071] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that
could permissibly vary without resulting in a change in the basic function to
which it is
related. Accordingly, a value modified by a term or terms, such as "about,"
"approximately," and "substantially," are not to be limited to the precise
value specified.
In at least some instances, the approximating language may correspond to the
precision of
an instrument for measuring the value. Here and throughout the specification
and claims,
range limitations may be combined and/or interchanged; such ranges are
identified and
include all the sub-ranges contained therein unless context or language
indicates otherwise.
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[0072] The embodiments described herein provide systems and methods
that introduce transmitter beacons and beacon detectors into an SAS or central
server
system to create a closed loop system that produces no significant
interference to sensitive
satellite receivers. The present embodiments implement actual real-time
measurements,
that is, a measurement-based protection (MBP) system, where each transmitter
beacon is
assigned its own unique identifier (ID) such that beacon detectors may be used
to build an
accurate and up-to-date propagation map or model. The MBP systems described
herein
further serve a dual purpose of allowing a central server to remedy the system
in the event
of a systematic change or actual interference experienced. In such cases, the
MBP system
utilizes the beacon transmitters and detectors to trace back to the source of
the interference,
and then affect system changes to protect particular FSS sites from the
encountered
interference.
[0073] In some embodiments, the techniques of the MBP system are
extended to improve or calibrate to the propagation model that may be used to
initially
assign resources to a new access point (AP). The MBP system may, in such
circumstances,
implement the techniques such that the beacon transmitters transmit
periodically to be
received by one or more beacon detectors within the transmission proximity.
Such a
management system is thus a dynamically adaptable to changes in the
environment of the
transmission path. For example, the MBP system would know, in real-time, the
effect on
the path loss from a sufficiently tall building being built (or removed)
between the beacon
transmitter and detector, and use this real-time measurement to more
accurately utilize the
transmission spectrum then can be done under the conventional approach that
only
performs estimate calculations based on maps. Furthermore, the MBP system is
capable of
adapting to seasonal changes between spring and fall to take into account the
differences in
propagation through trees, which is a major limitation of conventional
propagation tools.
[0074] More specifically, the present MBP system improves over
conventional CBSD to CBSD protection, e.g., in the priority access license
(PAL) and
general authorized access license (GAA) sub-bands, by using the actual path
loss
measurements from the CBSD, instead of relying on propagation models, which
are
imprecise in the CBRS band 3.55-3.7 GHz, as well as other frequencies,
generally due to
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clutter effects and building penetration loss as well as real time changes to
the
environment.
[0075] Because the MBP system of the present embodiments is
implemented as a closed loop, and thus creates effectively zero interference
(i.e.,
interference which has no meaningful effect on the satellite reception
itself), the system is
not limited to only CBSDs, but may also be applied with respect to APs and
user
equipment (UE/UEs) for mobile usage and small cell configurations. In an
exemplary
embodiment, individual beacon transmitters are configured to operate below the
satellite
noise floor, thereby allowing for significant link budget extension through a
wide
deployment of beacon transmitters and detectors.
[0076] Accordingly, the present systems and methods acknowledge the
appropriate purpose of the incumbent protection requirements of Part 96, and
propose an
alternative solution that implements an MBP scheme that achieves the same
protection
goals for FSS sites, but without over-protecting the FSS sites. The present
MBP schemes
may assume that all of the 575-600 MHz C-band downlink (i.e., between 3.6 ¨
4.2 GHz)
FSS bandwidth is co-channel to CBRS/RAP at every earth station site, or
alternatively
may, in an intelligent fashion, be further configured to consider co-channel,
adjacent
channel, second adjacent channel and aggregate interference limits to
optimally use the
spectrum. The conventional use of the conservative path loss predictions,
while achieving
the stated protection goals, unfortunately locks out CBRS/RAP usage by large
geographic
areas and results in inefficient use of the spectrum. In comparison, the
present MBP
schemes achieve the same protection goals, but also allow for control of
spectrum reuse in
a deterministic and non-interfering manner maximizing the spectrum utility.
The present
MBP systems and techniques further provide FSS receiver bandwidth usage
reporting to a
central server database (e.g., such as the SAS), which enables the central
server to enforce
FCC requirements without over-protecting (i.e., locking out usable spectrum).
Additionally, the MBP embodiments presented herein have more general
applications
across other bands and systems, and will result in a dramatic improvement of
spectrum
efficiency throughout.
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[0077] The present MBP system and methods herein thus implement an
empirical measurement scheme that improves over conventional CBSD-to-CBSD, or
RAP-
to-RAP, protection schemes and resource assignment calculations, which results
in
increased spectral efficiency, while more effectively managing potential
interference to the
FSS site from individual mobile transmitters or radio access points and
devices (e.g., UEs)
associated with respective APs. Through these innovative and advantageous
techniques,
the central server is further able to remedy a situation where interference
may be
encountered, for example, by instructing an eNodeB or AP to change its
frequency channel,
and through these changes, associated connected devices as well, to avoid
interference.
[0078] Additionally, if the noise floor of the FSS has increased and is
approaching an unacceptable threshold, due to the effect of the aggregation of
individual
mobile transmitters or radio access points and devices, the central server is
able to instruct
the devices in the vicinity of the FSS to reduce their transmitter power by
small increments
to bring the FSS noise floor to that of the original acceptable limit. The
improved model
derived by the present MBP system thus advantageously achieves this solution
in an
accurate manner, and with a minimum reduction(s) to the respective transmitter
powers,
and without a significant reduction in the range and coverage. These remedying
techniques
may therefore be extended to microcells that share the same spectrum.
According to the
present system and methods, new RAPs may be introduced within the vicinity of
sites that
are considered to already include a significant number of RAPs within a 40km
radius of the
FSS.
[0079] The present embodiments are further advantageously applicable to
operation within other frequency bands, including extensions to 5G, where
radio spectrum
sharing could be controlled and/or managed by a central server using various
sharing
strategies to allow multiple radio transceivers to coexist with each other and
other non-
controlled services (FSS in this example) that receive noise floor protection
and front end
blocking protection. These techniques are described more specifically below
with respect
to the following drawings.
[0080] FIG. 4 is a schematic illustration of a satellite service protection
scheme 400. In an exemplary embodiment, scheme 400 includes an FSS site 402
including
at least one earth station 404, having a dish and a frequency agile receiver
(not numbered),
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for receiving and decoding video/data streams from a satellite 406 (e.g., GEO
C-band
satellite). Scheme 400 further includes at least one AP 408. AP 408 may
include, without
limitation one or more of a wireless AP, an eNodeB, a base station, a CBSD, or
a
transceiver. In the exemplary embodiment, AP 408 is mounted on a first support
410.
However, many APs are within buildings. The MBP capabilities of scheme 400
though,
would take into account the penetrations loss of walls and metalized windows.
[0081] Authorization and resource allocation of FSS site 402 is governed
by a central server 412. In some embodiments, central server 412 includes an
SAS, and is
in operable communication with AP 408 over an AP data link 414. Additionally,
an FSS
reporting link 415 communicates the operating parameters of FSS site 402,
including
without limitation, coordinate, elevation, azimuth angle, elevation angle,
receiving
channel(s), satellite arc(s), frequency range, receiving channels, antenna
model, antenna
height, antenna gain, feed horn model(s), LNB model(s), service designator(s),
operation
status of the FSS earth station.
[0082] Scheme 400 also includes at least one beacon transmitter 416 and
at least one beacon detector 418. In the exemplary embodiment, beacon
transmitter 416 is
disposed in close proximity to AP 408, such as on first support 410, or
alternatively as an
integral component or function of AP 408. Similarly, beacon detector 418 is
disposed
within FSS site 402, in close proximity to earth station 404, and may be
structurally
mounted on the dish/antenna thereof, or alternatively on an independent second
support
420, or alternatively as an integral component of FSS site 402. In some
embodiments, each
Al' 408 includes at least one beacon transmitter 416, and each earth FSS site
includes at
least one beacon detector 418. In the exemplary embodiment, beacon transmitter
416
includes at least one transmitter, or alternatively, at least one transmitter
and at least one
receiver (not shown). Beacon detector 418 includes at least one receiving
portion. In some
embodiments, beacon transmitter 416 and beacon detector 418 includes
transceivers.
[0083] Beacon transmitter 416 is in operable communication with central
server 412 over a beacon data link 422, and beacon detector 418 is in operable
communication with central server 412 over a beacon measurement reporting link
424. In
an embodiment, beacon detector 418 is located outdoors, using a dedicated
antenna (not
separately shown). In another embodiment, beacon detector 418 is inserted in
the post-
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LNB signal chain (described further below with respect to FIG. 5). In some
embodiments,
beacon detector 418 may be located outdoors and attached to the station 404.
Beacon
detector 418 may separately communicate directly with central server 412.
[0084] Beacon detector 418 is configured to receive a direct beacon signal
426 from beacon transmitter 416. Beacon detector 418 may be integrated within
the
system of FSS site 402 or implemented as a standalone system. In the exemplary
embodiment, direct beacon signal 426 constitutes an in-band beacon RF signal
including a
unique ID, and is transmitted at a power that would not by itself cause any
meaningful
interference to FSS site 402. Beacon signal 426 may be transmitted on either
an on-
demand or a periodic basis. In other embodiments, the beacon can transmit the
unique ID,
its location, and its transmitter power, but is not limited to these
parameters. In the
exemplary embodiment, the location, frequency of operation, transmitter power,
etc. are
communicated by over data link 422 to maximize the range of detection. Beacon
transmitter 416 is further configured to have its own unique ID that can be
registered with a
database (not shown in FIG. 4) of central server 412. Accordingly, in the case
where AP
408 is a source of potential interference, central server 412 is capable of
not only
foreseeing or detecting the interference, but also of associating the foreseen
or detected
interference with the potential interference source (AP 408 in this example)
through the
unique ID. Moreover, by being able to identify the source of potential
interference, central
server 412 may be further configured to remedy the foreseen or encountered
interference
by, for example, instructing the interfering device to change its transmission
channel and/or
lower its transmission power or cease operation.
[0085] According to the exemplary embodiment illustrated in FIG. 4, the
in-band beacon transmission from beacon transmitter 416 allows measurement by
central
server 412 of the actual path loss between AP 408 and FSS site 402. In an
embodiment,
beacon detector 418 is further configured to include a means of measuring the
signal of the
interference and reporting the measured signal to central server 412 for
calculation of the
link loss. Furthermore, in contrast with FIG. 1, FIG. 4 does not illustrate
obstructions,
because the presence or absence of obstructions between AP 408 and FSS site
402 is
rendered irrelevant (for path loss determination purposes) by the nature of
real-time
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measurements. This MBP scheme is advantageously applicable to interference
calculations
performed by central server 412.
[0086] In an exemplary embodiment, central server 412 further utilizes
known locations (e.g., in the form of coordinates including longitude,
latitude, and
elevation) of both FSS site 402 and AP 408, as well as the transmit power and
antenna
pointing angles, to calculate the specific protection/protection scheme for
FSS site 402 with
respect to AP 408. In some embodiments, the protection scheme implemented by
central
server 412 further utilizes a path loss equation that utilizes empirical
measurement data
from one or more beacon detectors 418 (i.e., upon validation of the equation
by the FCC
and/or other relevant governing bodies). Central server 412 effectively
implements the
FCC protection requirements and, according to the embodiments herein, such FCC
protection requirements may be advantageously changed, for example, if the
protection
criteria was deemed to be more or less conservative by itself.
[0087] In the exemplary embodiment, transmissions from beacon
transmitter 416 (i.e., over links 422, 426) include the unique ID of the
transmitter, as well
as the transmit power of beacon transmitter 416 itself. Optionally, beacon
transmitter 416
further transmits location information (e.g., GPS data and/or map data),
and/or one or more
UEs associated with AP 408. Under this optional configuration, central server
412 may be
further configured to manage not only potential interference from AP 408, but
additionally
potential LTE interference along with consideration of the measured path loss.
In an
embodiment, the actual path loss is determined by central server 412 using an
in-band
measurement of a beacon received signal strength indicator (RSSI), and/or in
further
consideration of the transmitted effective isotropic radiated power (EIRP), as
well as a
measured antenna gain at one or both of AP 408 and earth station 404. Central
server 412
may then assign AP resources according to any and all of these measured
parameters,
[0088] In further operation, a wide-scale deployment of beacon detectors
418 at existing registered and unregistered FSS sites 402 (estimated at 8,000-
10,000 sites
or more at present) will provide a significant quantity of real-time
information about each
transmitting AP 408, and their respective effects on individual earth stations
404. The
amount of information is considerable that can be collected from thousands of
beacon
detectors (each having, for example, a range of approximately 2-5 km depending
on the
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morphology), in a broad deployment at thousands of FSS sites, which are much
more
highly concentrated in heavily populated areas. The beacon-based MBP
protection scheme
of scheme 400 thus realizes a two-fold advantage over conventional protection
schemes:
(1) individual beacon transmitters 416 may be configured to identify
themselves to other
devices within range, thereby allowing other system elements to carry out
measurements
and build propagation maps; and (2) in the event of a systematic change or an
emerging
problem, central server 412 may be configured to utilize the unique beacon IDs
to trace
back to the source of actual interference and implement remedial measures. In
the
exemplary embodiment, individual beacon transmitters 416 transmit to other
transceivers
(e.g., beacon detectors 418, central server 412, other beacon transmitters 418
having a
receiver component) within range, and feed the signal strength back to a
centralized
database (not shown in FIG. 4) of central server 412 (e.g., an SAS).
[0089] The MBP scheme of scheme 400 realizes still further advantages
over conventional protection schemes that utilize path estimates based on
locational maps
and propagation models. Conventional CBSDs and APs are known to include GPS
capability for an SAS to determine their respective locations on the map.
Propagation
models built by the conventional SAS, however, must make a number of numerical
assumptions (e.g., effects from building heights, number of windows, building
materials,
effects of trees, contours of the path, general clutter, etc.) to calculate a
path loss estimate
between the transmitter and the FSS site. According to scheme 400 though,
which
performs real-time measurements, the propagation model may be dynamically
built by
central server 412 from empirical data, and updated in a timely manner based
on actual
system conditions.
[0090] In one exemplary operation, scheme 400 implements an MBP
protection scheme that initially utilizes the conventional estimated
propagation maps. That
is, central server 412 may initially operate by performing calculations using
estimated
propagation maps to determine appropriate frequencies and power levels for
individual
APs 408. Over time though, as empirical data is collected from beacon
transmitters 416
and beacon detectors 418. Such real-time measurements of power and operating
conditions
may be fed back to central server 412 to update the initial calculations in
order to more
accurately assign (and reassign) resources under optimum conditions, Central
server 412 is
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then able to become aware of potential interference in real-time, and take
remedial
measures to resolve such problems, as described above.
[0091] In this example, beacon transmitters 416 will be in close proximity
to the channel on which transmission is sought, and centralized server 412 may
initially
instruct AP 408 to operate at a particular frequency and power level. However,
before an
individual AP broadcasts across the entire band, AP 408 may first cause a
beacon
transmitter 416, in close proximity to the particular band, to transmit a
beacon signal,
which may be within the band itself, or in an adjacent guard band. Thus, by
initiating
transmission from beacon transmitter 416 prior to broadcast from AP 408,
central server
412 is able to detect the beginning, learn the properties of the associated AP
408, and
determine whether operation of AP 408 would cause interference with respect to
a
particular FSS site 402.
[0092] In the case where central server 412 determines that a particular
AP 408 will cause interference, central server 412 may be further configured
to instruct AP
408 to lower its power, operate on a different channel, or simply deny
authorization and
hence operation. In at least one example, central server 412 may reevaluate
the beacon
power level and determine that the level is sufficiently low enough to allow
operation.
Because scheme 400 continually receives beacon signal information, if AP 408
is allowed
to broadcast but nevertheless causes interference, central server 412 is
capable of
correcting such a situation in a timely manner. In some embodiments, the band
gaps
between channels may be utilized in the MBP scheme of scheme 400. Because the
transmitted signal of the beacon itself does not cause interference to
satellite reception, the
beacon signal and the transmitter IDs may be transmitted in any of the
channels (12 in this
example) of the transmit spectrum. The ID of a particular beacon transmitter
416 always
stays the same, and therefore multiple beacons can overlap with other beacons
within the
same range, and still be decodable by central server 412, even in the case
where two
different beacons transmit within the same band gap.
[0093] According to the exemplary scheme 400, the transmitted beacon
signal itself may constitute low spectrum noise density in the C-band, may be
spread across
the whole of the band, or may be a narrow-band signal (e.g., noise) of the
order of about
10-1000 Hz. By itself, this spectrum density ¨ even across the whole of the
video channel
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- is not sufficiently high to cause any interference. According to exemplary
scheme 400,
the beacon is transmitted in a guard band. The beacon signal is though,
sufficiently high
that it may be actually measured, i.e., detected, by beacon detectors 418 and
the
information fed back to central server 412.
[0094] Scheme 400 is therefore configured to operate in multiple stages.
In an initial stage, AP 408 requests authorization from central server 412,
and central server
calculates, by an initial propagation model or actual measurements, a safe
frequency and
power for AP 408 to transmit In a second stage, beacon transmitter 416
transmits a
modulated signal to beacon detector 418, which may be then used by central
server 412 to
determine whether the amplitude will create interference. As discussed above,
when the
beacon signal is transmitted within the channel itself or in a guard band,
there is no
interference to satellite reception. The beacons' spectral power density may
operate below
the thermal noise level for the band itself. Furthermore, in the case where
the beacon
signal is out of band, or within band gaps, scheme 400 would be even more
tolerant of the
beacon, and may increase the beacon transmit power, and thereby potentially
the beacon
range as well. In a third stage, central server 412 determines that there is
no interference,
and informs AP 408 of the available resources for the broadcast. In the case
where initial
stages are based on propagation model estimates, subsequent real-time
measurements by
scheme 400 are utilized in later stages to dynamically manage AP 408.
[0095] According to the advantageous system and protection scheme of
scheme 400, the highly conservative safety margins that are built into the
conventional
protection schemes may be avoided, because scheme 400 is able to remedy
interference
that is encountered within the conventional safety margins. Scheme 400 is
capable of
registering the beacons and control the associated AP transmission through the
system-
wide capability of beacon self-detection. Scheme 400 thus effectively
functions as a
closed-loop system that continually measures, updates, and controls
broadcasting APs.
Because the beacon deployment according to scheme 400 allows for sufficiently
fast
communication and control measures, central server 412 is further configured
to sum
measured interference to almost zero, thus effectively providing no
significant interference.
Conventional protection schemes have not considered such a zero-interference
closed-loop
system.
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[0096] FIG. 5 is a schematic illustration of a satellite service protection
system 500 implementing protection scheme 400, FIG. 4, and similar components
between
system 500 and scheme 400 function in a similar manner to one another. In an
exemplary
embodiment, system 500 includes an FSS site 502 having a plurality of earth
stations 504.
In this example, FSS site 502 is a registered site. Each earth station 504
includes a dish and
a frequency agile receiver (not numbered), for receiving and decoding
video/data streams
from a satellite 506. System 500 further includes at least one or more
existing APs 508 that
have been authorized by, and are under the management and control of, a
central server
510 having a centralized database 512. Central server 510 may include, or be,
an SAS.
System 500 further includes a new AP 514 seeking authorization from central
server 510
(e.g., under PAL or GAA terms).
[0097] In the exemplary embodiment, each existing AP 508 includes at
least one existing beacon transmitter 516 as an integral component or function
thereof. In
other embodiments, existing beacon transmitters 516 may be separate and
distinct
components from corresponding existing APs 508. Similarly, new AP 514 includes
a new
beacon transmitter 518 as an integral component or function of thereof (as
illustrated), or as
a separate and distinct element. New AP 514 is in operable communication with
central
server 510 over new AP data link 520. In some embodiments, new beacon
transmitter 518
is in operable communication with central server 510 over a separate beacon
data link 522.
In other embodiments, the beacon transmitter and the AP communicate with
central server
510 over a single data link, as illustrated with respect to existing AP data
links 524 for APs
508. In the exemplary embodiment, each of beacon transmitters 516, 518 may
include a
transceiver (not shown), separate transmitting and receiving components,
and/or an
omnidirectional antenna. For ease of explanation, individual user equipment
(UEs) that
may be associated with APs 508, 514 are not shown.
[0098] New beacon transmitter 518 is configured to transmit a direct
beacon signal 526 for reception by one or more beacon detectors 528 at FSS
site 502. In
the exemplary embodiment, FSS site 502 includes at least one beacon detector
528 for each
earth station 504, and in close proximity to the respective earth station. In
an alternative
embodiment, FSS site 502 includes a single beacon detector 528 for a plurality
of earth
stations 504. In this alternative embodiment, the distance between the single
beacon
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detector 528 and each individual earth station 504 is known, and recorded in
central
database 512. A model for the FSS is built so that the single beacon detector
can model the
interference to each individual dish based on its operating parameters. Beacon
detectors
528 may be located indoors or outdoors, and may be integral to the structure
of a particular
earth station 504 (e.g., earth station 504(1) and beacon detector 528(1)), or
separate
components (e.g., earth station 504(2)/beacon detector 528(3), 504(3)/beacon
detector
528(3)).
[0099] More specifically, in the example where beacon detector 528(1) is
an integral portion of earth station 504(1), beacon detector 528(1) utilizes
LNB 530 as the
effective receiving portion of the beacon signal received by the dish. That
is, the dish of
earth station 504(1) detects direct beacon signal 526 from beacon transmitter
518 along
with the transmit spectrum from satellite 506. LNB 530 demodulates direct
beacon signal
526 along with the received transmit spectrum (not shown in FIG. 5), and
distributes the
demodulated beacon signal, according to an exemplary embodiment, along a
distribution
chain 532 to a rack of receivers 534 in a headend 536, to reach a reporter
538. In an
exemplary embodiment, reporter 538 is configured to filter and process the
demodulated
beacon signal, and then report it to central server 510 over a first beacon
measurement
reporting link 540. In an embodiment, first beacon measurement reporting link
540 is a
wired or wireless data link, or may be an RF communication. Thus, in this
example,
beacon detector 528(1) utilizes reporter 538 effectively as the transmitting
portion for the
beacon measurement.
[00100] In the exemplary embodiment, the MBP scheme further
configures beacon detector 528 such that a determination may be made if the
aggregate
signal level at the LNB input is greater than -60 dBm. In at least one
embodiment, this
determination is based on summing the individual measurements of each
transmitter
within, for example, a 40 km radius of FSS site 502. Beacon detection within
system 500
is further configured such that the system may further monitor (e.g., within
FSS site 502, or
externally by central server 510) the current, output level, output linearity,
and level of
known input signal of the LNB. System 500 is further configured to measure
noise level at
the output of the feed horn (or filter unit) of the LNB, or alternatively, the
carrier-to-noise
ratio (CNR), the bit error ratio (BER), and/or another metric downstream of
the LNB that
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indicates noise floor impairment. In some embodiments, system 500 is further
configured
to determine degradation of the noise floor at the intermediate frequencies,
and/or
degradation of receiver metrics that are attributable to the AP. For the CBRS
band, having
-129 dBm/MHz as the expected protection level, -10 dB I/N may be sought as the
noise
target. For other bands, a different noise target may be sought.
[00101] The integrated configuration of beacon detector 528(1) is
particularly advantageous to FSS sites having one or few earth stations, where
additional
hardware costs (e.g., additional antenna/transceiver for each dish) might not
be cost-
prohibitive, or in the case where other considerations would render multiple
external
antennas to be undesirable. Additional LNBs only marginally add to the
hardware cost of
an earth station, and many earth stations often include multiple LNBs for a
single dish. The
present embodiments therefore advantageously utilize one or more of the
relatively less-
expensive LNBs for beacon detection. According to this exemplary embodiment,
system
500 is able to tap into each FSS antenna signal distribution chain downstream
of the LNB,
and receive the beacon at the downconverted intermediate frequency (IF)
frequency of the
in-band beacon signal. According to this advantageous technique, the central
server is able
to avoid adjusting the beacon RSSI for the FSS dish antenna gain, since the
beacon signal
is received utilizing the FSS dish itself.
[00102] The implementation of integrated beacon detector 528(1)
provides the further advantage of enabling earth station 504(1) to detect
interference in
exactly the way that the interference will be affecting the earth station. In
other words, any
measured value at the reporter 538 will exactly represent the value of the
signal causing the
interference. In an exemplary embodiment, for narrowband signal, the integral
beacon
detector 528(1) further includes a sufficiently stable clock for each such
integral detector,
to realize a more efficient detection,
[00103] In some instances, and particularly for a narrow band signal, the
frequency stability of the oscillator used in the down conversion process in
the LNB may
be sufficient for a video signal, but may not by itself sufficiently stabilize
the position of a
beacon signal. Accordingly, in some embodiments, the local oscillator
frequency used for
down conversion may synchronize, for example, a GPS signal, such that the
beacon signal
is stabilized in order to speed the efficiency in which an auto-correlation of
the beacon
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signal can be performed. In other configurations of the beacon detectors
described herein,
an additional clock (frequency) is not required for efficient functionality.
[00104] In the example where detection is performed by a component
separate from the earth station, beacon detector 528 is an external antenna,
In some
embodiments, FSS site 502 includes up to one such external antenna for each
earth station
504. In other embodiments, FSS site 502 includes a single external antenna for
a plurality
of earth stations 504 at the single FSS site. In the case where beacon
detector 528 is an
external antenna located in close proximity to earth station 504, the beacon
measurement
reporting to central server 510 may be direct or indirect. More specifically,
beacon
detector 528(2) communicates directly with central server 510 over a second
beacon
measurement reporting link 542. In contrast, beacon detector 528(3)
communicates first to
a central processor (not shown) of FSS site 502 over an internal site
reporting link 544, and
FSS site 502 communicates directly with central server 510 over a site status
reporting link
546. In the exemplary embodiment, FSS site 502 communicates additional site-
related
information, including per-dish frequency usage, direction of alignment and
elevation, dish
size, GPS co-ordinates, etc., to central server 510 over site status reporting
link 546.
[00105] This site related information, such as direction of alignment and
elevation, can be provided dynamically to central server 510 by measuring
devices (not
shown) attached to each dish, and particularly for instances when the dishes
are aligned to
different satellites frequently. Alternatively, for dishes that are never
moved once they are
aligned, a database registration process (e.g., within central database 512)
could be used
which does not need the expense of separate dynamically reporting measuring
devices. In
at least one embodiment, the satellite measuring device includes a digital
compass and/or
an elevation angle-measuring component. In another embodiment, the measurement
device
is similar to a computer-controlled measuring device for a telescope.
[00106] According to the exemplary embodiments illustrated in FIG. 5,
central server 510 is capable of unlocking, for new AP 514, bandwidth that is
unused by
existing APs 516 (e.g., unused transmit spectrum portion 218, FIG. 2), thereby
significantly
increasing the spectrum utilization of the band. That is, as described above,
not all of the
twelve 40 MHz channels in the transmit spectrum will actually be demodulated
by every
dish receiver distribution chain at every FSS site.
System 500 thus advantageously
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protects the "used" channels at the appropriate level of co-channel
protection, and assigns
the conventionally "unused" spectrum to a new AP. In the exemplary embodiment,
central
server 510 further calculates blocking and noise levels to prevent degradation
of FSS
receivers, using the empirical information obtained by the MBP scheme.
[00107] Furthermore, in addition to the improved spectrum utilization,
systems and methods according to the protection schemes described herein
further achieve
advantageous reductions to the geographic size of the protection zone around
an FSS site.
That is, under current FCC protection schemes, an FSS site may be required to
have a 150
km radius co-ordination zone with formal written applications and studies
carried out on
each transmitter application against very conservative criteria. According to
the principles
of the present embodiments though, the FCC protection rules may be
successfully changed
to reduce the required radius of the protection zone immediately about the FSS
site, and
may further create outwardly-expanding geo-tiers of protection around new
reduced
protection radius. For example, as described herein, an immediate first
protection zone
(i.e., an exclusion zone) around an FSS site may be set to a 150 m radius. A
second geo-
tier zone, outside of the first protection zone, may be set to a 320 m radius
for small cell
use, and for operation within 280 MHz at 4W transmitter power. A third geo-
tier zone,
outside of the second geo-tier zone, could then be set to a 780 m radius, and
for operation
within, for example, 500 MHz at 4W. Beyond 780 m, higher powers are available.
These
tiers may be further modified according to particular system specifications.
[00108] In the case where FSS site 502 includes a single beacon detector
528 for a plurality of earth stations 504, the single beacon detector 528 may
further
implement multiple-input/multiple-output (MIMO) technology to effectively
increase the
gain and extended the range of system 500 and the protection scheme. In this
example, a
single beacon detection antenna may provide greater system visibility around
the
environment, and may also represent a lower hardware cost outlay for an FSS
site having a
large number of earth stations. Further to this example, because received
interference will
affect different earth stations in different ways, each of the plurality of
earth stations 504
may further be calibrated to the single antenna such that central server 510
is rendered
capable of determining the effect of the interference on a specific earth
station 504, and
then utilize the unique ID from the interfering source to remedy the
interference.
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Optionally, FSS site 502 includes at least one distributed detector 548 in
addition to one or
more beacon detectors 528.
[00109] In an embodiment, beacon transmitters 516 are transceivers, and
are further configured to detect a direct beginning signal 526 over respective
RF paths 550,
and report such measurement information to central server 510 over links 524.
Accordingly, by utilizing individual beacon transmitters for the dual-purpose
functionality
of transmission and detection, system 500 is rendered capable of significantly
increasing
amount of real-time information that can be used to measure, manage, and
remedy
interference for a particular FSS site. This capability is particularly
advantageous in the
case where FSS sites are not densely populated (and thus potentially fewer
available
beacon detectors), but APs seeking to utilize the transmit spectrum are more
numerous.
The APs themselves thus perform a level of self-policing among a community of
APs.
[00110] In an exemplary embodiment, such beacon transceivers can be
implemented in either the hardware or the software of an eNodeB or AP, or may
constitute
a separate device having a separate antenna, or utilizing a base station
antenna. In some
embodiments, transmission of the beacon signal may be periodic, on-demand, or
according
to programming. Where the beacon signal is managed according to a program, in
at least
one embodiment, program may include instructions to terminate the beacon
transmission
once the eNodeB or AP has been authorized by the central server, but continue
to allow
beacon detection as desired. The beacon transmission program may be stored in
a central
database 512 and run by central server 510, or may be executed at the AP
level. In some
embodiments, central database 512 further includes data regarding the
frequency of
satellite 506, one or more frequencies actually received by earth stations
504, as well as the
direction of orientation and elevation of the earth station dish(es). All such
information
may be used to calculate initial resource allocations, as well as empirical
interference
management by central server 510.
[00111] FIG. 6 is a flow diagram for an exemplary process 600 for
operating satellite service protection system 500, FIG. 5. In operation,
process 600 begins
at step 602, in which small cell communication is initiated by an AP. In one
example of
step 602, new AP 514 is a small cell access point that initiates communication
by one or
more of powering up, restarting, wakening from a sleep mode, etc. In step 604,
AP 514
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submits an authorization application to central server 510, including one or
more of a
unique small cell identification code, location coordinates, a requested
maximum power
from the whole small cell, minimum power level(s) for effective operation, a
requested
frequency channel or channels, elevation, antenna and/or MIMO status, whether
the AP use
is indoor or outdoor, and an estimated maximal user number. In the exemplary
embodiment, AP 514 communicates submitted information over a wired Internet
connection. In an alternative embodiment, AP 514 communicates submitted
information
over the air by an agreed signaling channel.
[00112] In step 606, central server 510 calculates a path loss based on a
propagation model using the information submitted from AP 514 in step 604. In
at least
one example of step 606, central server 510 further utilizes information
previously stored in
a central database 512 to calculate the path loss. Once the initial path loss
is calculated,
process 600 proceeds to step 608. Step 608 is a decision step. In step 608,
process 600
determines, based on the calculations from step 606, whether unavoidable
interference
would result at any FSS earth station from the operation of AP 514. That is,
in step 608,
central server 510 determines whether there is a feasible channel and power
level at which
AP 514 may provide effective coverage for small cell users and, at the same
time, will not
cause interference to F SS site 502. In at least one example of step 608, the
criteria for this
interference determination may vary depending on the frequency of operation,
the
aggregate background noise level contribution, the number and distances of
APs, etc.
[00113] If, in step 608, process 600 determines that interference will
occur, process 600 proceeds to step 610. In step 610, central server 510
rejects the
application from AP 514. In further operation of step 610, AP 514 waits for a
time period
and then returns to step 604, where AP 514 submits a new application to
central server 510,
including timely updated small cell information, or central server 510 informs
AP 514 of a
change in conditions.
[00114] If, however, in step 608, process 600 determines that interference
will not occur, process 600 proceeds to step 612. That is, process 600
determines that no
interference occurs when central server 510 calculates the existence of a
maximum power
level and a frequency channel for AP 514 that will ensure both feasible and
interference-
free small cell communication. In step 612, central server 510 sends
permission to AP 514,
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including the approved frequency channel, the approved maximum power, and
other
relevant operational information. The approved frequency channel/maximum power
sent
by central server 510 is the same or different from the channel/power
originally requested
by AP 514, based on calculations by central server 510 regarding the available
spectrum
and/or measured empirical information that updates the initial propagation
model. In step
614, AP 514 transmits a beacon having a central frequency derived from the
approved
frequency channel sent in step 612. In at least one example of step 614, the
power level of
the beacon is also derived from, but will be significantly lower than, the
approved
maximum power sent in step 612. In an alternative operation, AP 514 transmits
the beacon
in an close adjacent guard band. The power level of the beacon may thus be
higher if the
beacon is out of band, but not high enough such that the FSS reaches -129
dBm/MHz.
Spectral density is a factor, and thus a beacon at 4W/40MHz could have higher
power at
100kHz, for example.
[00115] In step 616, central server 510 collects data from one or more
beacon detectors 528, including one or more of the received beacon power, the
detector
coordinates, etc., and calculates a measurement-based path loss based on the
collected data.
In the exemplary embodiment, the beacon data is additionally collected from
beacon
transmitters 516with beacon receiving functions, distributed sensing
locations, or other in-
range detection equipment that is communicatively coupled to central server
510. In some
instances, where the beacon cannot be detected by one or more desired beacon
detectors,
central server 510 may use the data collected from the other detector/sensing
locations. In
at least one example of step 616, central server 510 prioritize the collected
beacon data
according to the location of the detector (e.g., distance of a detector from a
transmitter may
be considered as a factor) and/or the reliability of the particular detection
component (e.g.,
not all transmitters and detectors will be of the same known quality). Once
the path loss is
calculated, process 600 proceeds to step 618.
[00116] Step 618 is a decision step, and operates similarly to step 608.
That is, in step 618, based on the calculated path loss from step 616, central
server 510
determines whether unavoidable interference may occur at any FSS earth
station(s) if AP
514 operates at the frequency channel that was approved for beacon
transmission, or in a
guard band. That is, in step 618, central server 510 determines whether there
is a power
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value at which AP 514 can provide effective coverage for particular UEs and,
at the same
time, will not cause interference to particular FSS sites 502. If unavoidable
interference is
foreseen, process 600 returns to step 610. If the central server 510
determines that there
exists a maximum power value that will guarantee feasible and interference-
free AP
communication, process 600 proceeds to step 620.
[00117] In step 620, central server 510 sends permission to AP 514 with
detailed information including an approved maximum power and an allocated
frequency.
Similar to step 612, based on calculations by central server 510, the approved
maximum
power and/or the allocated frequency in step 620 may be different from either
or both of
the request powers/frequencies from application step 604 or approval step 612.
Process
600 then proceeds to step 622 in which AP 514 begins small cell communication
at the
approved frequency channel (e.g., from step 612 or step 620) and approved
maximum
power level (e.g., from step 620), and continues the small cell communication
for a
communication period. After the communication period, process 600 returns to
step 604,
where AP 514 submits an application for revalidation, including updated
information (e.g.,
the number of small cell users associated with AP 514).
[00118] Referring back to step 620, process 600 also proceeds to step 624,
in which central server 510 updates its propagation model based on collected
measurement
data from beacon detectors 528, beacon transmitters 516, and other detection
components
in the system, if any.
[00119] In step 626, small cell communication from AP 514 is terminated.
Step 626 occurs, for example, when AP 514 is placed into sleep mode, powered
off (e.g.,
without sending an acknowledgement in time to central server 510), or
otherwise rendered
non-operational. In various circumstances, step 626 may occur at any time in
process 600
after step 602. Upon termination of small cell communication from AP 514,
process 600
proceeds to step 628, in which central server 510 determines that AP 514 has
ceased
communication and any radiation/transmission at the protected band. Process
600 then
proceeds to step 624.
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[00120] Process 600 is therefore particularly applicable to MBP schemes
for FSS sites in the CBRS band/C-band and devices (e.g., CBSDs, APs, LIEs,
etc.) sharing
the 3.55-4.2 GHz spectrum, as well as other bands where sharing radio
resources is
centrally enforced based on the interference contribution of individual
transmitters and a
spectrum sharing strategy. Furthermore, process 600 may add additional steps
to those
described above, or in some circumstances, omit particular steps that may
become
redundant or unnecessary in light of other conditions, or may be performed in
a different
order. Additionally, process 600 may further adopt one or more of the
following
considerations.
[00121] In some embodiments, central server 510 is configured to
determine if AP 514 is within the required protection distance from any
registered FSS
sites, or within the coordination distance of existing APs. If AP 514 is
within the
protection or coordination distance, central server 510 may instruct AP 514 to
activate its
beacon transmitter 518. In some embodiments, as described above, beacon
transmitter 518
may communicate directly with central server 510, and outside of the immediate
control of
Al' 514. That is, even in the case where the components are integral, AP 514
and beacon
transmitter 518 need not directly communicate with one another. In such
circumstances,
the beacon link 522 and the AP data link 520 to central server 510 may be
separate and
independent from one another.
[00122] In other optional features of system 500 and process 600, central
server 510 may be configured to pass the unique ID code to beacon transmitter
518 for
transmission over the air on a particular beacon frequency, and beacon
transmitter 518 may
begin transmission using this ID code, assigned by central server 510, in its
data payload.
In an embodiment, the data payload may include one or more of the unique ID,
the location
of beacon transmitter 518/AP 514, and the transmit power. In at least one
embodiment, the
data payload further includes information related to UE utilization, as well
as means to
migrate interference of a UE to a satellite disk. For example, when a UE is
determined to
be too close in proximity to a protected FSS site 502, central server 510 may
instruct the
UE to change its frequency out of the protected band. Additionally, in the
exclusion zones
around an FSS site where any transmission is considered to cause interference,
the UE may
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be instructed, with coordination by the mobile core, to operate in another
frequency band
(e.g., 900 MHz).
[00123] In some embodiments, APs 508, 514 are further configured to
directly or indirectly communicate information between one another about
individual UEs
associated with that respective AP. In at least one embodiment, according to
particular
operational conditions, such communication occurs over fixed network to reduce
the
payload of the beacon and maintain a maximum link budget.
[00124] In some embodiments, central server 510 is optionally configured
to proactively contact beacon detectors 528 that are within a protection
distance, and
inform the receivers thereof to report any beacon IDs received during an
assigned
measurement. In some instances, central server 510 may be optionally
configured to
directly contact selected beacon transceivers at a known nearby existing AP
508, as needed
for GAA/PAL protection calculations, to initiate measurement of beacon signal
526 from
new beacon transmitter 518. The number of beacon detectors 528 disposed at FSS
site 502
is optional, and may be based on morphology, clutter, and expected propagation
conditions.
Similarly, the height of the particular antenna, as well as its gain, may be
assigned at the
discretion of the operator. In some embodiments, a particular unique beacon ID
may not
be known to an FSS (e.g., where it may be desired to protect the integrity of
the beacon
measurement scheme), but will be stored in central database 512 for
confirmation by
central server 510 where necessary.
[00125] In some embodiments, central server 510 may also be configured
(e.g., through software programming or hardware components) to query a
management
system/processor (if known and/or present) of an FSS site to update
information in central
database 512 regarding bandwidth usage, antenna azimuth, elevation angle
receiving
schedule, noise measurements, etc. Similarly, beacon detectors 528 may be
programmed
(or may be responsive to control by a program from another component) to
automatically
report to central server 510, upon detection of any beacon ID, the received
beacon ID, the
RSSI, and/or the signal-to-noise-ratio (SNR). Optionally, central server 510
may be further
programmed to wait for a timeout, and note if FSS site 502 has identified the
beacon ID
assigned to new AP 514 during a measurement period, and then update the FSS
site
parameters in central database 512 if such beacon information has been
received.
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[00126] In some embodiments, central server 510 is further programmed
to calculate the path loss between each AP 508, 514 and each FSS site 502 for
each beacon
detector 528, and compute the potential for interference to each FSS site dish
antenna.
Such calculations may further consider the received RSSI values, antenna
azimuths, and
gain patterns at both the respective FSS sites and the APs, and further take
into account the
computed path loss between the AP and FSS site locations based on the discrete
and
continual beacon measurements. Central server 510 may still further be
configured to
calculate the path loss between new AP 514 and existing APs 508, and calculate
the
potential for interference by new AP 514 to each existing AP 508. In this
example, such
calculations may further consider antenna parameters, FSS site parameters, and
the
computed path loss between AP's based on real-time beacon measurements.
[00127] In all of the examples described above, central server 510 is
configured to utilize the results of the beacon measurements, as well as
updates from the
FSS site parameters, to continually monitor the operating parameters for AP
(and also UE)
communication with respect to one or more FSS sites. Such operating parameters
include,
without limitation, the power levels, antenna gain/orientations, and transmit
frequency.
[00128] The systems and methods described herein therefore realize
significant advantages over the conventional protection schemes by allowing
for the
determination of the actual path loss between an AP/CBSD and an FSS site, and
also the
loss from AP/CBSD to AP/CBSD. The present embodiments thus achieve in-band
beacon
transmission-to-detection with greater than a 180 dB link budget (e.g., for a
single AP) or
up to 200 dB link budget (e.g., for multiple APs) for satellite dishes with
low elevation
angles to Geo-stationary satellites. According to the present embodiments,
measurement of
third party signals by an AP (e.g., from known transmitters in the direction
of the FSS site
or other APs) further allows a significantly improved capability to estimate
in-building loss
and path loss distance-based exponents, as well as means for remedying
interference. In at
least one embodiment, a plurality of central servers are networked together to
share
information and complete tasks. In this example, the plurality of central
servers may be
supplied by different companies and/or operators, work and communicate
together in a
cloud-like network, and/or assign one central server as a master server to
manage other
central servers.
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[00129] The present systems and methods further allow for the
determination of the individual interference contribution from each identified
transmitter.
In some embodiments, the individual interference contribution may be
determined using
formats for narrow band beacons and reporting, such as weak signal propagation
reporting
(WSPR), for example, in order to determine path loss within the gain profile
of the satellite
aperture. The central server is able to prioritize and control AP transmitter
parameters to
reduce the overall transmitter contributions such that they fall below the
noise floor, and/or
a particular desired noise target for all the key interference thresholds.
According to these
advantageous capabilities, other transmitters outside of the aperture can be
successfully de-
prioritized, multipath contributions can be recognized and managed, and
overall noise
optimization can be obtained.
[00130] According to the present embodiments, further advantages may
be realized with respect to mobile device management. For example, UEs
associated with
an AP/CBSD may contribute interference to an FSS site, even at relatively low
transmitter
power. Under the protection schemes and systems herein though, UEs may
themselves
deploy a beacon signal manner similar to that described above with respect to
the APs, and
thus more effectively report their association with a particular AP/CBSD, and
hence the UE
location (from the HE beacon or directly from the AP) to the central
server/SAS.
Accordingly, the actual path loss associated with each UE may be determined,
and thus the
level of interference from that HE. If the interference from a particular HE
is determined
to exceed a chosen threshold, the AP may cause the UE to move to another band,
such as
the macro-cell which uses a different frequency band to the satellite system
and does not
cause any interference.
[00131] In an exemplary embodiment, the AP (or CBSD) reports a
number of UEs associated with that particular AP such that the effective
transmitter power
is proportionally increased to that of the number of UEs, and in consideration
of the
transmitter power of each individual UE. If this effective transmitter power
becomes too
high, that is, causes a potential interference problem, then the individual
UEs may be
instructed to operate in another band, such as a macrocell. In this example,
the individual
UEs would not be required to utilize the beacon transmissions, since the range
of
association distance between the UE and the AP is considered relatively small
in
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comparison with the distance of the AP to the FSS site. Therefore, utilization
of accurate
approximations for these individual UEs (in close association distance)
renders optional
this use of the beacon technology at the individual HE level.
[00132] The systems and methods herein further advantageously provide
FSS site monitoring and reporting to the central server of real-time channel
usage at each
FSS receiver/dish pairing. Under these techniques, receiver frequency
assignment can be
fixed or dynamic, depending on satellite and FSS customer needs, and such
assignments
may be continually tracked by the central server to prevent interference by
CBRD, Radio
Access points, UEs or other interfering devices. FSS receiver bandwidth may
therefore be
automatically detected, or alternatively, manually input if desired.
[00133] When the actual received bandwidth is known at each location
and signaled to the central server, the full 500 MHz transmit band will not
need 180 dB or
200 dB of co-channel protection from the CBRS fundamental emission. Instead,
as little as
104 dB of protection may be adequate to protect FSS to the FCC-mandated level,
such as
for the second adjacent band. Furthermore, the multi-protocol receiver may be
installed at
FSS dish to identify CB SD signal sources and report RSSI and identification
data to central
server. In this example, these co-channel protection values are included for
illustration
purposes, and not in a limiting sense. These values may reflect upper limits
for satellites
with low elevation angles within the central beam, but may which have small
beamwidth
angles. The 180 dB value may therefore be representative of a single AP, and
may be
greater (e.g., the 200 dB value) for multiple APs within the central beam.
Interference
falling within the central beam angle (e.g., 3 degrees) is of greater
significance than
interference outside of the central beam. That is, a greater number of APs may
be
permissible nearer the FSS site, but outside of the central beam angle.
[00134] As described herein, the central server is configured to act to not
only approve applications to transmit, but also to monitor, measure, manage
active
participants, and further to remedy potential and actual interference. The
central server of
the present systems and methods thus acts upon bandwidth usage reporting by
the FSS sites
and the measurement-based protection scheme system. Measurements by beacon
receivers,
multi-protocol receivers, FSS satellite program receivers, other APs/beacon
transmitters,
and even UEs, are reported to directly or indirectly to the central server to
determine one or
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more of: (i) path loss between the FSS site and the AP/CBSD; (ii) path loss
between the
FSS site and a UE associated with the AP/CBSD (e.g., with location
information); (iii) path
loss between a new AP/CBSD and one or more existing APs/CBSDs; (iv) impairment
of
the FSS noise floor; (v) degradation of FSS receiver performance; (vi) the
identify of a
particular AP/CBSD that is raising the noise floor at a specific frequency and
for a
particular FSS site dish; (vii) any interference caused by a UE in close
proximity to the FSS
site; and (viii) interference from the aggregation of transmitters across the
whole satellite
band that impacts on the linearity of the LNB.
[00135] According to the present embodiments, central server is still
further configured to take one or more of the following remedial measures to
mitigate
interference and migrate the source of interference to a non-interfering
communication
status: (i) collect input information and determine appropriate actions to
take regarding
interfering APs/CBSDs/UEs; (ii) issue commands to AP/CBSD to modify operating
parameters (e.g., transmit power, operating frequency/bandwidth, antenna
pointing angle or
direction, etc.) of new and existing APs/CBSDs based on FCC rules, equitable
resource
allocation calculations, changes to RF propagation, etc.; (iii) issue commands
to specific
UEs (in conjunction with an associated mobile network or other networks) to
modify
operating parameters, including changing channel of operation (e.g., in the
case of a mobile
network, to that of the macro-cell that is in a different band to the FSS
site); (iv)
continually monitor the operation of an initialized AP/CBSD over time for
changes in
propagation conditions and other factors could change the interference
environment; (v)
regularly monitor status reports from FSS receivers and/or master scheduler
regarding
bandwidth utilization at each site, and recalculate resource allocation values
using this
updated information; and (vi) modify frequency assignments of existing
APs/CBSDs in an
impact area of FSS site according to changes in FSS frequency usage.
[00136] A person of ordinary skill in the art, upon reading and
comprehending this written description and accompanying drawings, will
understand the
applicability of the present embodiments beyond the specific examples
described herein.
For example, the principles of spectrum sharing in the C-band and CBRS band
may be
applied to protection schemes in other bands, and particularly to the "6 GHz"
bands,
namely, the 5.925-6.425 GHz and the 6.425-7.125 GHz bands, which are presently
utilized
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for satellite uplinks. Such innovative 6 GHz band protection schemes are
described
immediately below. The present inventors further envision implementing the
advantageous
beacon detection systems in a "stoplight" system for governing the deployment
and
operation of particular beacon detectors.
BEACON BASED PROTECTION FOR THE 6 GHZ BAND SPECTRUM
[00137] As described above, the disclosed beacon protection system is
particularly useful for sharing the 3.6-4.2 GHz spectrum between the FSS earth
stations
and other terrestrial radio system users. The following embodiments describe
innovative
systems and methods for extending these innovative techniques to the 5.925-
6.425 GHz
spectrum, sometimes referred to as the "designated 6 GHz" spectrum.
[00138] A key difference between the 3.6-4.2 GHz spectrum and the 6
GHz spectrum is that the 3.6-3.7 GHz and 3.7-4.2 GHz spectra are used to
receive signals
from space, whereas the 5.925-6.425 GHz spectrum is used for earth-to-space
communications. The 6 GHz spectrum thus involves different propagation physics
that are
associated with the protection of this particular spectrum range, and also
includes different
users desiring to share this portion of the spectrum. For example, at present,
in the United
States, the 5.925-6.425 GHz spectrum has approximately 27,000 or greater
microwave
point-to-point users. Additionally, the 6 GHz spectrum is significantly less
suited for use
by mobile users, which, in the main, is the 3.6-4.2 GHz spectrum. However,
although the
3.6-4.2 GHz spectrum is presently targeted for 5G mobile use, the 3.6-4.2 GHz
spectrum
has relatively fewer available microwave point-to-point links.
[00139] Although the following embodiments are described with respect
to extending the beacon protection techniques, described above, to the 6 GHz
spectrum, the
person of ordinary skill in the art will understand, upon reading and
comprehending the
present specification and drawings, that these innovative techniques may be
further
extended into other satellite bands and spectra for future shared use. The
following
embodiments provide a solution to a recently-proposed challenge, which
recommend
portions of the 3.7-4.2 GHz spectrum, presently used for satellite downlinks,
be allocated
for licensed mobile communications, while designating the 6 GI-lz spectrum
(5.925 to
7.125), which includes the uplink counterpart, for unlicensed use. One recent
proposal is to
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free 1700 MHz of spectrum: 500 MHz for licensed purposes; and up to 1.2 GHz
for
unlicensed purposes. The systems and methods herein extend the beacon-based
protection
techniques, described above, will advantageously manage sharing of this new
proposed
usage of the 6 GHz spectrum in a significantly more efficient manner.
The 6 GHz Spectrum (5.925-7.125 GHz)
[00140] In the United States, the 500 MHz of bandwidth in the 5.925-
6.425 GHz band (hereinafter, the "Lower 6 GHz" band) of the 6 GHz spectrum is
presently
allocated exclusively for non-federal usage, on a primary basis for FSS (Earth-
to-space)
and fixed services (FS). Similar allocation of the Lower 6 GHz band is
implemented
across the world.
[00141] For the F SS uplink, the 5.925-6.425 GHz band (Earth-to-space) is
associated with the 3.7-4.2 GHz band downlink (space-to-Earth), which are
collectively
referred to as the "C-band" in conventional parlance. In this application, the
conventional
parlance is used for ease of explanation, and is not intended to be limiting.
That is, a
person of ordinary skill in the art will understand that, by "C-band," the
present
embodiments are intended to generally refer to the 3-8 GHz spectrum, and
satellite systems
and/or mobile communication systems that operate within this spectral range,
and
frequently with respect to similar system elements/components (e.g., satellite
dishes, earth
stations, transmitters, receivers, APs, UEs, etc.). Moreover, the person of
ordinary skill
will understand that the systems and methods herein are not limited to only
the particular
spectral ranges, or portions thereof, described herein.
[00142] At present, there are approximately 1,535 earth station licenses in
the 5.925-6.425 GHz band. Although most of these earth stations operate at
fixed
locations, some earth stations have been disposed on mobile vessels but still
operate in this
band on a primary basis. In at least one instance, mobile devices of one
operator have
been licensed to transmit to geostationary satellites in order to provide
consumer-based text
messaging, light email, and Internet of Things (IoT) communications, thereby
protecting
terrestrial operations by using a database-driven, permission-based, self-
coordination
authorization system. At present, the 5.925-6.425 GHz band is also used for
the
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transmission of command signals transmitted by the earth stations, typically
near 5.925 or
6.425 GHz.
[00143] In present FS implementations though, the 5.925-6.425 GHz band
is heavily used. FS licensees are, for example, authorized to operate point-to-
point
microwave links with up to 120 MHz of paired spectrum for each authorized
path.
Individual paired channels under these licenses may be assigned in specified
bandwidths
ranging from 400 kHz up to 60 MHz. Present public records indicate that
greater than
27,000 licenses have been issued for point-to-point operations in this band.
Such
operations are known to support a variety of critical public services, such as
public safety
(including backhaul for police and fire vehicle dispatch), coordination of
railroad train
movements, control of natural gas and oil pipelines, regulation of electric
grids, and
backhaul for commercial wireless traffic.
[00144] At present, the 5.925-6.425 or
Lower 6 GHz, band portion
of the 6 GHz spectrum is the most heavily used FS band for long links, with
approximately
63,260 transmit frequencies in use. The lower 6 GHz band is otherwise known to
only
provide significant applications for FSS uplink earth stations. However,
because FSS
uplink earth stations do not conventionally include receiver capabilities at
the 6 GHz
spectrum, the FSS uplink earth stations presently would not require protection
from the FS
usage.
[00145] Accordingly, it is presently easier to coordinate with earth stations
at 6 GHz than it is to coordinate at 4 GHz, because there are fewer earth
stations to
consider in the 6 GHz spectrum. Moreover, because the transmitters are at a
higher
frequency (6 GHz) than the receivers (4 GHz), other users of the 6 GHz
spectrum
implement highly directional systems that often exhibit lower gain in
comparison with FSS
in the 4 GHz band. Thus, many earth stations at the 4 GHz spectrum are
configured to
receive-only. Furthermore, coordination zones for the 6 GHz spectrum are
respectively
smaller, and a 6 GHz FS operator is better able to accept the risk of incoming
interference
from an uplink earth station. Additionally, many 6 GHz earth stations are
configured to
transmit to only one transponder on one satellite for decades at a time. An FS
user has
been able to conventionally assume that other frequencies and pointing
directions will
remain vacant. In contrast, at 4 GHz, the FS user is required to always
protect even
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portions of the band and arc that its particular earth station does not use,
and/or is never
expected to use.
[00146] Nevertheless, 6 GHz uplink earth stations still have the potential
to cause interference to FS receivers. As with the 4 GHz downlink earth
stations, the 6
GHz uplink earth stations always have the right to operate on any frequency in
the band,
pointing to anywhere in the entire geostationary arc thereof, at any time and
without notice.
Therefore, even though it is easier to site FS links for reliable operation at
6 GHz than it is
at 4 GHz, potential interference problems still remain.
[00147] Remaining portions of the 6 GHz spectrum are defined by the
FCC Notice of Inquiry (NOT). That is, the NOI further describes the 6.425-
7.125 GHz
band to include three different segments, with each segment having a different
respective
application.
[00148] The first segment of the 6.425-7.125 GHz band is the 6.425-6.525
GI-[z segment. The 6.425-6.525 GHz segment has a mobile allocation with
Broadcast
Auxiliary Service and Cable TV Relay applications. The 6.425-6.525 GHz segment
presently has no FS allocation, and therefore no public position regarding the
use of the
6.425-6.525 GHz segment has been taken by the Fixed Wireless Communication
Coalition
(FWCC).
[00149] The second segment of the 6.425-7.125 GHz band is the 6.525-
6.875 GHz segment (hereinafter the "Upper 6 GHz" band, or FS band). At
present, the
upper 6 GHz band is used less intensively by earth stations, but has a
narrower bandwidth
than the Lower 6 GHz band. Only in the past few years have operators been able
to use
Upper 6 gigahertz band channels having a bandwidth wider than 10 MHz. In
contrast, the
Lower 6 GHz band has had available 30 MHz channels for many years, and more
recently,
60 MHz channels. Because of these considerations, the Upper 6 GHz band has
experienced significantly less total activity than has the Lower 6 GHz band,
and using
approximately only half as many transmit frequencies. The usage of these upper
6 GHz
band though, is growing, in the present embodiments offer advantageous
solutions to
successfully manage this increased usage.
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[00150] The third segment of the 6.425-7.125 GHz band is the 6.875-
7.125 GHz (hereinafter, the "7 GHz" band), which primarily serves the
Broadcast
Auxiliary Service and the Cable TV Relay Service, similar to the first
segment. In contrast
to the first segment, however, FS links are permitted in the 7 GHz band, but
these FS links
are not permitted to intersect with the service areas of television pick up.
Such limitations
have thus severely restricted FS access in the 7 GHz band. Similar to the
first segment
though, the FWCC also has not stated a public position regarding future usage
of the 7
GHz band.
[00151] The systems and methods herein therefore advantageously utilize
the 6 GHz band to address considerations arising from the reallocation of the
former 2 GHz
FS band, and also in consideration of the problems, discussed above,
experienced in
coordinating with FSS earth stations at 4 GHz. The present Upper and Lower 6
GHz
bands/band segments thus represent the only remaining FS bands that implement
frequencies low enough to span tens of miles. These two band segments are
discussed
together herein because they have similar technical characteristics and are
used for similar
purposes. These two band segments are further discussed together because the
FS links in
both segments (at present and for expected future use) will require the
highest levels of
protection from other services.
[00152] The present systems and methods additionally allow devices to
advantageously operate both in the lower 6 GHz band and in the spectrum
designated (by
the FCC) for Unlicensed National Information Infrastructure (U-NI!) use.
Because the
lower 6 GHz band is considered close to the U-Nil spectrum, the extension of
the present
beacon detection schemes to the 6 Gfiz band provides a technical solution to
beneficially
enable U-Nil devices to flexibly operate in both spectra. Such devices may
thus operate
with wider channel bandwidths and higher data rates. Such devices would also
realize a
significantly increased flexibility for all types of unlicensed operation.
[00153] As described herein, "U-Nil devices" refers to unlicensed devices
that presently operate in the 5.15-5.35 GHz and 5.47-5.725 GHz bands. As
unlicensed
devices, such U-NII equipment operates under Part 15 rules of the FCC. Devices
that
operate pursuant to Part 15 generally share spectrum with allocated radio
services, and
therefore must operate on a non-interference basis, that is, such unlicensed
devices are not
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permitted to cause harmful interference, such as from allocated radio services
and
authorized users. Such unlicensed devices are further required to meet
technical
requirements or standards designed to minimize the risk of harmful
interference.
Manufacturers though, enjoy significant flexibility with regard to the
hardware and
applications that may be implemented to satisfy these technical requirements,
which has
contributed to the significant recent growth of various technologies such as
Wi-Fi.
[00154] In 2013, the FCC proposed to make additional spectrum available
for U-NII devices in the 5.35-5.47 GHz and 5.85-5.925 GHz bands, but the
National
Telecommunications and Information Administration (NTIA) concluded in 2016
that there
is no viable solution for U-NII devices to share the 5.35-5.47 GHz band with
incumbent
federal systems. The present systems and methods avoid this problem by
providing
spectrum sharing techniques that allow U-Nil devices to operate in the 6 GHz
band.
[00155] The present embodiments further advantageously allow for
coordination with existing fixed microwave frequencies, which has proven
difficult for
conventional systems. The present embodiments still further enable
coordination with
developing cm- and mm-Wave 5G system technology. At present, a fixed microwave
applicant coordinates a particular frequency band and a particular azimuth.
All other
frequencies and directions are thus available to other applicants. In
comparison, to
coordinate satellite earth station frequencies, an FSS applicant will
routinely coordinate the
entire band, as well as every pointing direction toward every geosynchronous
satellite. By
default, the FSS implementations use full-band and full-arc coordination, even
if accessing
only one transponder on one satellite, and fixed microwave applicants must
protect even
unused satellite coordination. The difficulties of the fixed microwave
coordination are
illustrated below with respect to FIGS 7 and 8.
[00156] FIG. 7 is a graphical illustration depicting a comparison of
conventional fixed point-to-point distributions 700 and 702, for the 4 GHz
band (downlink)
and Lower 6 Gflz band (uplink), respectively. As illustrated in FIG. 7, both
distributions
700 and 702 represent full-band, full-arc, and fixed microwave links.
Distribution 700
illustrates how the 4 GHz band presently includes approximately 939 of such
links,
whereas distribution 702 illustrates how the Lower 6 GHz band includes
approximately 57,
654 of such links.
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[00157] A comparison of distributions 700 and 702 further illustrates the
applicability of the present techniques with respect to exclusion zones.
Distribution 700,
for example, demonstrates how the downlink exclusion zones are very large and
difficult to
avoid, thereby resulting in fixed microwave implementations being barred from
significant
portions of the geographical territory. Distribution 702, on the other hand,
demonstrates
how uplink exclusion zones are considerably smaller in comparison, and easier
to avoid.
Nevertheless, in the uplink, is considered risky under conventional techniques
to use vacant
channels in an FSS protection/exclusion zone.
[00158] FIG. 8A is a graphical illustration depicting a conventional earth
station location 800 for the 4 GHz downlink band. FIG. 8B is a graphical
illustration
depicting a conventional comparison plot 802 of a trend 804 (shown in yearly
increments)
of the number of fixed microwave earth stations in the 6 GHz uplink earth
station transmit
band and a similar trend 806 of the fixed microwave earth stations in the 4 GI-
[z downlink
band. As can be seen from FIGS. 8A-B, fixed microwave coordination at 4 GHz is
conventionally considered to be impossible over much of the country. The
beacon
detection scheme described above though, solves this problem by providing a
fixed
microwave coordination scheme at 4 GHz. However, as described further below,
this
innovative beacon scheme may be even further extended for shared use
applications in at
least the designated 6 GHz band.
[00159] FIG. 9 is a graphical illustration of a chart 900 depicting relative
percentages of existing earth station database problems conventionally
encountered, such
as earth stations being (i) more than 100 feet from license, (ii) built and
decommissioned,
or (iii) not found. Based on a sample of 300 earth stations to determine usage
of registered
earth stations, chart 900 demonstrates a relatively low utilization (35%, in
this example) in
the FCC database. It should be noted though, that chart 900 does not take into
account
usage of unregistered earth stations. Nevertheless, chart 900 is based on an
FWCC study
that has been credibly confirmed by other studies.
[00160] Conventional interference mitigation techniques have been unable
to fully resolve these problems. A collaboration of Working Parties of the
International
Telecommunication Union (ITU) drafted a recommendation for potential
mitigation
techniques to improve operation of International Mobile Telecommunications
(IMT) in the
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3.4-3.6 GHz band without causing interference to FSS earth stations, but the
working
parties have not reached a jointly approved solution. The ITU Radio
Communication
Sector (ITU-R) has proposed several other techniques to mitigate interference
with
coexisting terrestrial and satellite systems in the C-band (assuming a maximum
EIRP of 59
dBm for terrestrial systems), but none of these proposed techniques have
effectively
overcome the basic incompatibility between IMT systems and FSS earth stations.
The
beacon detection techniques of the present embodiments, on the other hand,
successfully
resolve these known incompatibilities, and within the parameters described
herein.
[00161] Band segmentation, for example, has been proposed as one
conventional solution for terrestrial service/satellite system coexistence.
Real-world
deployments, however, have conclusively shown that harmful interference may
still occur
even when the two respective systems operate in non-overlapping bands. One
particular
study indicated that a 2 km separation distance from all satellite receivers
was
conventionally necessary to prevent terrestrial mobile systems from causing
harmful
interference. This harmful interference arises due to the limited capability
of (i) terrestrial
systems to limit out-of-band emissions, and (ii) satellite receivers to filter
out unwanted
emissions in adjacent bands.
[00162] Additional filtering techniques have been proposed to address
these adjacent band problems, but such additional techniques have also been
unable to
successfully manage the terrestrial/satellite coexistence. Two interference
mechanisms are
particularly related to these adjacent band problems: (1) unwanted emissions
from
terrestrial base/mobile stations (e.g., operating in the C-band) can generate
interference to
earth stations in other parts of the same band; and (2) since the LNBs and
LNAs used on
FSS earth stations are designed to receive a broad spectrum (i.e., including
the entire C-
band), the power radiated by terrestrial base/mobile stations can overdrive
the respective
amplifier of the first block, thereby compromising the linear response
thereof. This
overdrive effect on the LNB is reduced by including additional filtering
(e.g., bandpass,
etc.) on the FSS earth stations, however, the application of such additional
filtering to the
FSS earth station would prevent the station from using portions of the C-band,
which
would compromise the service thereof
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[00163] Moreover, additional filtering solutions are difficult to apply in
the case of transportable earth stations, since, by the nature of their
operations, the
geographical location and receiving frequencies of the transportable earth
station may vary
significantly and often over time. A typical Satellite News Gathering (SNG)
earth station,
for example, may be employed to transmit and receive carriers on different
satellite
transponders, from the number of different geographical locations, in a
relatively short
interval of time. Furthermore, the introduction of an RF filter between the
FSS earth
station antenna output and the input to the amplifier of the first receiving
block Will
generate loss. Consequently, the system equivalent noise temperature will
increase
significantly for any 0.1 dB of attenuation, on the order of approximately 2.3-
8%.
[00164] Filters that are conventionally used in the C-band are known to
have an insertion loss of approximately 0.5 dB, thereby resulting in an
increase in the noise
temperature on the order of approximately 43%, or 1.54 dB. Additionally, an
increase to
the satellite downlink carrier EIRP will results in a reduction to the overall
capacity of the
satellite system. Because many FSS earth stations are receive-only, and thus
are frequently
unlicensed or "blanked licensed," the inability of a system administrator to
have access to
all of the necessary information places further practical constraints against
the application
of additional filtering to the FSS earth station. Another conventional
filtering technique
addresses the interference from unwanted emissions by applying rejection
filtering to the
transmitting terrestrial base/mobile stations. This technique reduces
emissions outside of
the assigned frequency blocks, but interference is still known to occur within
a separation
distance of up to approximately 4 km.
[00165] The deficiencies in these conventional proposals are resolved
according to the innovative techniques of the systems and methods herein,
which
dynamically allocate the spectrum between the respective terrestrial and
satellite systems.
Under these dynamic spectrum access solutions, terrestrial systems within a
given territory
are enabled to use the portions of the spectral band that are not being used
by ground-based
satellite systems in the vicinity. According to these advantageous techniques,
terrestrial
systems are effectively able to "choose" the appropriate frequency of
operation, according
to the real-time information collected through the disclosed auxiliary system,
which
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includes a network of beacons installed on the FSS earth station antennae,
and/or a
database with geographical data.
[00166] As described for the downlink 4 GHz/C-Band embodiments,
above, the FSS receiver is highly sensitive to interference from other users.
In this
embodiment though, the above dynamic spectrum techniques are further adapted
to
additionally protect the 6 GI-Iz band, where the FSS transmitter potentially
creates
interference to other users. That is, according to the embodiments described
herein,
systems and methods are provided that advantageously protect both a particular
FSS from
others' interference, and others from potential interference from the
particular FSS. As
described further below, both techniques largely employ the same
infrastructure.
[00167] Therefore, the present solution protects not only users of the
downlink (e.g., multiple system operators (MS0s) of a cable network, content
providers,
etc.), but also other users that may be affected by the uplink transmissions.
By providing
such two-way protection using largely the same beacon detection/transmission
subsystem
overlay to existing network infrastructures, the present embodiments vastly
expand the
protection that may be implemented with respect to the several communication
bands, but
without significantly increasing the implementation costs in proportion
thereto. Using this
subsystem infrastructure, the present inventors contemplate that the
innovative techniques
described herein may be further extended into other communication bands
according to the
same scale of economy.
[00168] Previous auxiliary information systems have been proposed, but
the design and implementation of such conventional auxiliary systems was
complex, and
the required maintenance thereof very expensive. In contrast, the beacon
detection system
of the present embodiments is integrated, in a relatively inexpensive manner,
within the
existing the FSS infrastructure. Through this innovative integration, a
real time,
measurement-based propagation is determined, which allows exclusions zones to
be
reduced to as little as only a few hundred meters in radius, e.g., for the
circular portion of
the "teardrop shape" of a typical transmission. Furthermore, even in the
pointed portion
(i.e., in the direction of transmission) of the teardrop shape, the beamwidth
thereof will be
relatively narrow, thus providing for a significant reduction to the total
exclusion zone area
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in comparison with conventional approaches. This dramatic reduction to the
size of the
exclusion zones also results in a comparable increase to the value of the
spectrum.
[00169] The reliability of the present embodiments is achieved according
to the simplified architecture of the auxiliary beacon detection system, as
well as the built-
in capabilities to verify the accuracy of the real-time measurements of a
particular beacon
from a number of other beacons within range. In a given geographical area, the
manager of
the respective terrestrial system is required to decide whether a base/mobile
station may
transmit or mute any transmission on the basis of the information concerning
the real-time
usage of the C-band by FSS earth stations in the surrounding area (and then
continue to
update such decisions). Accordingly, the correct functioning of the auxiliary
measurement
system, as well as the timely accuracy of the information it delivers, is of
great significance
to prevent interference between the systems.
[00170] The operational requirements of FSS downlink earth stations are
generally subject to constant and rapid variations. Accordingly, to maximize
flexibility in
response to such variation, the earth stations are generally designed to
receive multiple
carriers of bandwidth, and typically between 4 kHz and 72 MHz in portions of
the C-band.
Additionally, the frequencies at which a particular earth station may operate,
and the
pointing direction of the respective earth station antenna, are not fixed; the
frequencies and
pointing directions may also be varied at any given point in time by the
respective satellite
operator according to a number of various operational circumstances, many of
which may
be unforeseeable. The present embodiments therefore provide an innovative
solution that
advantageously allows earth stations to access the entire space segment, such
that the earth
stations may respond without any disruption to changes in operational
conditions, which
often occur instantly and without notice.
[00171] As described further below with respect to FIG. 10, the present
systems and methods implement a closed loop system that is capable of
planning,
monitoring, and controlling interference in a dynamic manner. This dynamic
closed loop
system advantageously allows shared use of the relevant spectrum among
competing users
to achieve the maximum commodity of the available spectrum. The innovative
approaches
described herein measure propagation losses in real-time, thereby avoiding the
use of
conventional propagation planning tools that are known to be intrinsically
inaccurate. The
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measurement-based propagation techniques of the present embodiments further
avoid the
limitations of conventional shared-use planning, which utilized propagation
tools that were
required to make very conservative data assumptions in order to protect the
most sensitive
user of the particular system being planned, That is, the conventional
propagation
techniques necessarily introduced significant inefficiencies to the spectrum
abuse by being
forced to allocate the spectrum according to the requirements of only the most
sensitive
user.
[00172] FIG. 10 is a schematic illustration of a shared use system 1000. In
the exemplary embodiment, system 1000 includes an FSS site 1002, a central
server 1004,
a first FS transceiver 1006 (or a transmitter/receiver combination) including
a first beacon
transmitter 1008 and a first beacon detector 1009, a second FS transceiver
1010 including a
second beacon transmitter 1012 and a second beacon detector 1013. In the
exemplary
embodiment, FSS site 1002 includes at least one beacon detector 1014. In the
example
illustrated in FIG. 10, first beacon transmitter 1008 is located within the
vicinity of a
plurality (i.e., 1-n) of neighboring APs 1016 (e.g., Wi-Fi access points), and
each
neighboring AP 1016 includes a respective neighboring beacon transmitter 1018.
In this
example, elements of system 1000 are similar to elements in protection scheme
400, FIG.
4, and system 500, FIG. 5, and that are designated by similar labels. One of
ordinary skill
in the art will appreciate that additional elements from FIGS. 4 and 5 may be
incorporated
into system 1000 as described above, but that not all such elements are
repeated in FIG. 10
for ease of explanation.
[00173] In the exemplary embodiment, first FS transceiver 1006 operates
a point-to-point microwave link 1020 with second FS transceiver 1010, and
central server
1004 receives fixed network data communications 1022 (e.g., LAN, WAN,
Internet,
another type of electronic network, etc.). Additionally, first FS transceiver
1006 may be in
operable communication with central server 1004 over a first data link 1024,
and second
FS transceiver 1010 may be in operable communication with central server 1004
over a
second data link 1026. Similar to the embodiments disclosed with respect to
scheme 400
and system 500, above, each of respective beacon transmitters 1008, 1012, and
1018 over
beacon links 1028. System 1000 may further include an FSS reporting link 1030
for
communicating operating parameters of F SS site 1002 with central server 1004.
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[00174] In the exemplary embodiment, central server 1004 is in operable
communication with the beacon detectors 1009, 1013, 1014 to receive
information
regarding detected beacon transmissions. Central server 1004 may further be in
operable
communication with relevant transceiver portions (not separately shown) of APs
1016 that
are configured to detect neighboring beacon transmissions, e.g., over beacon
links 1028. In
some embodiments, beacon links 1028 are configured as fixed communications,
and may
share the same link (e.g., fixed network data communications 1022) used to
authorize
transmission. In an embodiment, first and second data links 1024 and 1026
also, or
alternatively, are fixed communications included in fixed network data
communications
1022, which may represent a broadband fixed link or a radio link (e.g., a
mobile base
station in a rural area, where a fixed cable link is very costly, and all
communication to and
from the base station is instead by way of a point-to-point microwave link).
Accordingly,
fixed network data communications 1022 may represent a separate fixed link, or
the
aggregation of all fixed links where individual system components do not
communicate
over their own RF path.
[00175] In operation of system 1000, operation of FSS site 1002 within
the vicinity of first FS transceiver 1006 generates FSS interference 1032 (or
potential
interference) into the operation of FS transceiver 1006 from the satellite
uplinks (not
separately shown) associated with FSS site 1002. In a related manner,
operation of
neighboring APs 1016 within the vicinity of first FS transceiver 1006
generates Wi-Fi
interference 1034 (or potential interference) into first FS transceiver 1006
from the
respective Wi-Fi operations. Each of respective beacon transmitters 1008,
1012, and 1018
otherwise operates according to the principles described above.
[00176] That is, in the example illustrated in FIG. 10, the auxiliary
measurement-based techniques of the downlink system are advantageously adapted
for the
uplink embodiment of system 1000 to enable the shared use of the Lower 6 GHz
band for
microwave point-to-point FS and satellite uplinks. As described above, the 500
MHz
bandwidth of the Lower 6 GI-[z band in the United States is allocated
exclusively for non-
federal use, on a primary basis for FSS (Earth-to-space), and for FS, such as
microwave
point-to-point, and FS licensees may be authorized to operate point-to-point
microwave
links with up to 120 MHz of paired spectrum for each authorized path.
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[00177] In accordance with system 1000 though, each user of the Lower 6
GHz spectrum, for both FSS (e.g., FSS site 1002) and FS (e.g., first FS
transceiver 1006,
second FS transceiver 1010), incorporates a radio beacon (e.g., beacon
transmitters 1008,
1012, beacon detector 1014) as part of the transmission of the user's spectrum
utilization.
The respective radio beacon thus uniquely identifies each respective user or
neighbor as the
potential source of interference. Also similar to the embodiments described
above, the
beacons may be included within guard bands, co-channels, or the unused portion
of the 500
MHz of bandwidth in the Lower 6 GHz spectrum.
[00178] In some cases, a Wi-Fi AP (e.g., AP 1016) is located indoors and
operates at low power (e.g., < 1W), system 1000 may be configured such that it
may
disregard, or give lower priority to, a beacon transmission from the low power
AP.
According to an exemplary embodiment, such low power, "non-interfering" (i.e.,
low risk
of potential interference) APs may be exempt from including their own beacon
transmitters. In contrast, Wi-Fi APs located outdoors, and employing higher
power
transmissions, could be required to include at least one beacon transmitter
configured to
operate according to the principles described herein, since such outdoor/high
power
operation represents a significantly higher risk of potential interference.
Overall system
costs may be reduced by exempting common, known, indoor, low power, low-risk
APs.
[00179] In an alternative example, the effect of large number of indoor
Wi-Fi APs in a cluster may collectively increase the potential risk of
interference, even
where individual ones of the cluster might not. In this case, system 1000 may
be further
configured to model such clusters as a single effective AP 1016. Where central
server
1004 determines that the cluster AP 1016 represents an interference risk,
central server
1004 may be further configured to cause small decreases in the transmitter
power of all
APs in the cluster to reduce the interference risk. In this example of system
1000
illustrated in FIG. 10, central server 1004 is configured to individually
communicate with
each AP in the cluster. In other embodiments, central server may communicate
with a
primary AP in the cluster, and the primary AP communicates with other,
secondary, APs in
the cluster. As described above, each AP may also include its own beacon
detector.
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[00180] In one embodiment, the transmitter power of the single cluster AP
is calculated using the MBP model for each individual transmitter of the
respective low
power APs in the cluster. This calculation is of particular value in the
formation of an
optimization strategy for resource assignment of or to the individual APs in
the cluster.
The central server is thus further advantageously capable of re-optimizing the
transmitter
powers, using the MBP measurement(s), as conditions dynamically change. In
another
embodiment, the aggregate power of the cluster is directly measured, without
necessarily
identifying the individual contribution thereto of each AP in the cluster. By
these
techniques, system 1000 provides further benefits over conventional systems in
that central
server 1004 may thus advantageously enable frequency planning of individual Wi-
Fi APs,
to improve service therebetween, such as through the assignment of different
channels to
avoid interference between the respective neighboring APs. In some instances
of indoor
AP use, the beacon detection range for the indoor AP may be limited.
Nevertheless, in
such cases, the indoor AP may be managed such that it has sufficient power to
report to
nearby neighboring APs to enable central server 1004 to build up a map of
potential
interference that includes such indoor APs.
[00181] Thus, as with the downlink embodiments described with respect
to scheme 400 and system 500, the beacon transmission scheme of the uplink
system 1000
enables the identification of the registered transmitter by transmitting the
unique ID of the
transmitter in a beacon. Also similar to the downlink beacon implementation,
the beacons
in the uplink scheme are further enabled to transmit other useful infolination
associated
with the service use, such as the transmitter and beacon GPS co-ordinates,
azimuth, used
frequencies, transmitter power, antenna parameters, system parameters, etc. In
an
exemplary embodiment, transmission by the beacon includes only the unique
beacon ID to
minimize the information content of the transmission, and the hence associated
bandwidth,
and to extend the range for subsequent beacon detection through optimum signal
formatting. Thus, each user of the Lower 6 GHz spectrum incorporates a data
connection
(e.g., first data link 1024, second data link 1026, reporting link 1030) to a
database of the
central server (e.g., central server 1004) to register operating parameters,
and other key
parameters in real-time, for use of the Lower 6 GHz spectrum by the respective
user.
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[00182] As illustrated in FIG. 10, central server 1004 is similar to central
server 412, FIG. 4, and central server 510, FIG. 5, in that central server
1004 represents a
new form of SAS system. Central server 1004 therefore provides yet a further
improvement
over conventional SAS systems that have been developed to introduce greater
flexibility of
spectrum sharing. Although some conventional SAS systems have historically
included
capability for scalability, the present systems and methods achieve
significantly greater
scalability potential through use of the improved and simplified propagation
model
described above.
[00183] In operation, central server 1004 performs database registration
similarly to the processes described above for the downlink embodiments. The
database
registration of central server 1004 includes all of the operating system
parameters,
including the beacon ID, the transmitter GPS co-ordinates, azimuth,
frequencies of use,
transmitter power, and other key operating requirements. In some embodiments,
the
beacon is separate from the transmitter. For example, a farm of satellite
uplinks may
utilize a single beacon transmitter to transmit all such information together,
or as a series of
IDs. The registered operating parameters of each beacon are relevant to the
system
operating parameters, and are thus sufficient to calculate potential
interference. In an
exemplary embodiment, after a user (or AP) is registered in the database (not
separately
shown in FIG. 10) of central server 1004, only the beacon ID is subsequently
transmitted,
since all subsequent detections of the beacon transmission will enable central
server 1004
to perform a lookup within its database for the ID of the detected beacon to
determine other
useful information required for subsequent control within the closed loop of
system 1000.
That is, the beacon operating parameters are provided at the time of
registration, and do not
need to be subsequently transmitted to beacon detectors. Subsequent changes to
the beacon
operation need only be sent to central server 1004 as a single registration
update.
[00184] In an embodiment, the number range associated with the beacon
ID is configured to transmit sufficient bits of information to uniquely
identify a user. For
example, if a 16-bit word is used for the beacon 1D, as many as 65,536 users
may be
supported. At present, this exemplary bit structure is more than sufficient to
address the
number of present FSS and FS users, which is approximately 1,500 and 27,000,
respectively, as demonstrated above. As the number of FSS and FS users
increase, the
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present systems and methods may be further advantageously scaled to
accommodate such
increases without system redesign. In one example, the word range of the
beacon may be
further reduced, but while supporting an even higher number of users. That is,
ff) numbers
may be reused for where both users of the same ID are geographically separated
from each
other. Because both FS and FSS use confined transmitter radiation beams, the
known
geographic separation may significantly reduce ID word size. The present
inventors
contemplate that, given that the number of main FS users is 27,000 at present,
this number
reuse technique will enable a reduction of a 16-bit word to less than 12 bits,
with a reuse
factor of 16.
[00185] In practice, the beacon detection systems are installed at the
location of each spectrum users, e.g., at the receiver site thereof, to detect
potential
interference to the user's service. In the exemplary embodiment, beacon
detectors are
installed at each FS receiver, which are much more sensitive to FSS
transmitter
interference than are the FS transmitters. Although the present embodiments
are therefore
particularly advantageous for FS users, the FSS beacon detectors nevertheless
also provide
further significant benefits to the overall system, namely, the measurement-
based
propagation techniques, which may be implemented at relatively low marginal
costs in
comparison with conventional techniques. The overall cost savings are even
greater when
implementing the uplink protection techniques together with the downlink
protection
techniques, described above, since both embodiments substantially utilize the
same system
beacon transmitter/detector infrastructure overlay and functionality.
[00186] In further operation of system 1000, the system detection
sensitivity is sufficiently high such that, in normal use, potential
interferers are identified
well below the system noise floor before actually causing any interference. In
practice,
during the initial planning phase for the introduction of a new radio AP or
FS, the operating
parameters of the radio AP/FS are determined in advance to avoid any potential
interference from the FSS, based on dynamic knowledge of the FSS operating
parameters
and the use of the MEP for greater accuracy. Similarly, for point-to-point
microwave FS
implementations, system 1000 further advantageously enables planning for new a
FS use in
such a manner that an existing FS will not cause interference to the new FS.
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[00187] Accordingly, the further implementation of the present auxiliary
beacon transmission and detection systems onto the newly-introduced radio
AP/FS
provides distinct advantages over conventional techniques. First, the present
systems and
methods provide a failsafe in the case of an unforeseen event; the real-time
detection of the
beacon may be used to control the operating parameters of the FS users.
Second, the
present systems and methods provide a real-time measurement based propagation
(MBP)
system that enables accurate pre-planning of the initial operating parameters
open FS user
to effectively avoid potential interference before the interference occurs. In
combination,
both of these distinct advantages form a closed loop system that
advantageously enables
the dynamically adjustable planning, monitoring, and control of interference
in real-time.
Furthermore, operation of the present central server improves Wi-Fi service by
assigning
non-interference channels to adjacent Wi-Fi APs, and point-to-point FS systems
may be
planned in advance to avoid interference from existing operations.
[00188] According to the advantageous principles herein, shared use of
the Lower 6 GHz band may be further extended for future Wi-Fi, as well as
other radio
APs and satellite uplinks. The Lower 6 GHz band is ideally suited for such
spectrum
extension for Wi-Fi use. The Lower 6 GHz band is close to the spectrum that
the FCC has
designated for U-NIT use. The present embodiments thus avoid the problems
identified by
the NTIA, above, and further, overcome the NTIA conclusion that there is no
viable
solution for U-NIT devices to share the 5.35-5.47 GHz band with incumbent
federal
systems. The present systems and methods provide an innovative technical
solution in the
downlink for FSS/FS systems that allow each system to economically share the
central
infrastructure.
[00189] In the exemplary embodiment, each radio AP, such as a Wi-Fi
AP, innovatively transmits a radio beacon in its guard band or co-channel
which uniquely
identifies the beacon transmitter. As described herein, the present
embodiments distinguish
between radio/Wi-Fi APs, on the one hand, and FS devices, on the other hand,
as different
devices. As described above, unlicensed devices, such as U-Nil equipment
operating
under the Part 15 rules, achieve significantly lower EIRPs, and may therefore
be managed
differently from other devices, according to such factors as indoor/outdoor
use, and/or
individual and collective operating power. Another significant difference is,
for FS, the
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Azimuth may be obtained during this coordination. However, in the case of
small cells, the
small cells are either omnidirectional, or else it is hard to obtain their
respective Azimuths.
However, according to the present systems and methods, the respective small
cells may
include beacons attached thereto, and the respective beacons may be detected
at both the
FS and FS S sites and the collected measurements passed thru to the central
server.
[00190] In at least one embodiment, as described above, the interference
from such small cell devices may be further reduced in the case where the
small cell
devices are mandated only for indoor use only. Although such mandates would be
difficult
to enforce, the known shielding effect of walls and metallized glass windows
significantly
reduces the potential for external interference on or from the small cell
transmission. In an
embodiment, system 1000 may be further configured to detect the presence of a
small cell
device operating outside of its mandated use.
[00191] To support a much large user group, the number space (word
length) allocated to the beacon is accordingly increased as well. Where the
same beacon
frequencies are used, a contrast may be seen between the approximately 27,000
present
microwave point-to-point links, against the millions of Wi-Fi access points
presently
available. Nevertheless, as described above, the number range of the IDs
associated with
these Wi-Fi APs may be significantly reduced by the present number reuse
techniques.
[00192] In at least one embodiment, the systems and methods here further
utilize two different beacon frequencies/frequency ranges: (i) one for FS
microwave users,
which is likely to require a significantly faster response time for any
unforeseen
interference; and (ii) another for the Wi-Fi radio APs, where a primary form
of interference
may be associated with an increase in the noise floor of the system, which in
turn reduces
the system capacity, and thus results in a much slower response time to
potential
interference, Accordingly, these different number ranges may support the
enhanced link
budget performance of the entire beacon system. Alternatively, if the link
budget of the
beacon detection system is increased to account for the relatively high
propagation loss at
the Lower 6 GHz band in comparison with the 4 GI-[z band, then a single beacon
frequency
may be implemented with an expanded beacon ID number range. In one embodiment,
an
indoor-only Wi-Fi AP may not employ its own beacon, as the cost of
implementation may
be greater than the risk of interference in comparison with an outdoor AP.
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[00193] Referring back to FIG. 10 and system 1000, advantageous fixed
network data communication techniques are achieved, which avoid potential
interference
into the FS from satellite uplinks (e.g., FSS sites), and from Wi-Fi APs. In
both instances,
the present systems and methods equip the satellite uplinks, the FS, and the
Wi-Fi APs with
beacon transmitters. The associated beacon receivers according to system 1000
will be, in
the exemplary embodiment, geographically distributed.
[00194] The downlink implementation of system 1000 retains many of the
innovative techniques of the uplink system 500 and associated protection
scheme 400, as
well as a substantial portion of the same hardware, and therefore the
implementation of
both of the downlink and uplink schemes together realizes significantly
greater cost
advantages. In an embodiment of system 1000, the beacon receiver may utilize
one of
several multi-antenna technologies, such as MIMO, to improve receiving
diversity and
sensitivity. Given the concentration of microwave links in populated areas,
and the number
of existing microwave point-to-point links to be approximately greater than
27,000, the
present techniques are highly effective at measuring virtually all potential
interference
sources alone. In additional, the approximately 4,700-10,000 FSS in the 4 GHz
band would
also include beacon detectors. Many of these will have co-located the 4 GHz
uplinks while
separate Lower 6 GHz would also have beacon detectors.
[00195] For example, in the case of a single beacon detector at a given
location, a steerable antenna may be utilized similar to that used with MIMO
technologies,
in order to detect beacons from different directions. Thus, each satellite
dish located on a
particular site can be pointed in a different direction, and this ability to
steer the antenna
advantageously enables a more accurate measurement of the effect on each
separate dish.
[00196] In combination, the novel and improved beacon sensor network
overlay could, at present, include as many as 30,000-40,000 sites in populated
areas of the
United States, with an equivalent cellular coverage of approximately hundreds
of meters of
radius. In an exemplary embodiment, the link budget of system 1000 is
approximately 200
dB or greater, thereby enabling system 1000 to adequately measure interference
significantly below the system noise floor. The present embodiments thus
further improve
over conventional schemes that realize link budgets greater than 200 dB
because, as
described herein, once a device is registered (including its operating
parameters), only the
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beacon ID needs to be transmitted periodically to monitor environment changes
which
would affect interference propagation. In the exemplary embodiment, other
changes to the
operation of a user or AP would be instigated by the central server and
directly recorded
within its database, and would not need to be communicated to by the user or
AP itself.
The present embodiments are therefore particularly useful with respect to
multiple access
schemes developed for IoT, and may further implement Zadoff-Chu functions used
in LTE,
or Weak Signal John Taylor (WSJT) used in amateur radio communications.
[00197] The central server according to the present techniques therefore
represents a new and improved form of a Spectrum Access Sharing System, which
represents a key innovative component in the present closed loop system that
plans,
monitors and controls interference dynamically. This dynamic control is best
illustrated
according to the following advantageous examples of implementing the present
systems
and methods.
[00198] (1) In the initial planning phase for the introduction of a new
radio AP or FS, the central server can supply operating parameters on grant
for such
successful introduction, because the central server has dynamic knowledge of
the operating
parameters of the FSS and other existing FS use. At present, FS usage requires
study prior
to grant. According to the present systems and methods though, the FS grant
may
automatic from the central server. As described above, the central server may
optionally
utilize conventional propagation models and optimization theory as a starting
point, but
automatically grant the new FS use based on the additional dynamic knowledge
provided
by the new beacon infrastructure overlay. The present systems and methods are
able to
advantageously consider the influence of neighboring APs sharing the band, and
then
calculate aggregation to the system noise floor, as well as direct
interference.
[00199] (2) With knowledge of the transmitter powers, their EIRPs, and
their location, together with the measurements from the beacon detectors, the
present
central server is able to more reliably build accurate propagation maps, with
real-time
measurements. Such real-time dynamic calculations thereby avoid the
problems
experienced through use of conventional propagation tools, which are
intrinsically
inaccurate because they necessarily require highly conservative assumptions to
protect the
most sensitive users in the model.
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[00200] (3) Once the operating parameters of a user/AP have been
established and registered, the central server is able to verify an optimal
solution for each
system element using only the received beacon transmissions (and subsequent
real-time
detections, such as by other beacon detectors in the vicinity), and the real-
time
measurements thereof, to accurately calculate the propagation model). The
central server
may reliably then confirm the propagation loss, and only then authorize the
particular
operation.
[00201] (4) Once the initial settings have been confirmed, then the central
server monitors the specific interference, as well as the source thereof, to
look for any
changes in the environment which would necessitate changes in real-time. Most
of the
changes detected would be below a performance threshold, thereby allowing
small
infrequent changes. In some embodiments, such changes may be localized to a
small area
to avoid global changes (e.g., using optimization goals/optimization theory,
and/or by using
a pool of reserved frequencies in that local area). However, should a strong
interference
occur, then the detection of the associated beacon would allow rapid remedial
action.
[00202] The techniques and inventions described above introduce new in
the innovative systems and methods that enable a significantly expanded system
for sharing
access to the same spectrum, but described herein with respect to the
designated 6 GHz
band, both between an FSS and an FS, and also between radio access points and
Wi-Fi
access points. All such embodiments form a closed loop system that has the
capability to
plan, monitor and control interference in a dynamic fashion, such the system
will allow
shared use of the spectrum amongst competing users such that the maximum
commodity of
the spectrum is achieved.
[00203] The principles of the systems and methods described herein may
be further adapted to: massive MIMO transmissions, utilizing beamforming at
the
AP/mobile base station to reduce interference to satellite systems in the
downlink; beacon
formatting and transmission schemes to allow for gradual power increases to
the beacon;
extending the effective detection range of an individual beacon beyond a 2.4-5
km limit for
an individual site, where a network of widely deployed beacons may be directly
or
indirectly reported back to a central server, and particularly across
populated areas; include
on-site geo-distributed antenna arrays to reduce inaccuracies caused by
multipath
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transmissions; computer programs and models to further refine the collection
of real-time
empirical data and more accurately manage spectrum sharing and re-use across a
range of
transmission bands; and technology upgrades to AP devices to include their own
beacon
detectors to better systematically link with FSS sites and other APs for more
accurate path
loss estimates and more secure protection.
[00204] The advantageous closed-loop configuration of the present
embodiments therefore provides significant versatility in the implementation
of protection
schemes utilizing the disclosed beacon detection techniques. That is,
interference is
effectively eliminated irrespective of whether a spread spectrum is utilized,
or a
narrowband transmitter. Beacon detectors may be deployed as integral
components of the
satellite dish, or as separate antennas, but neither deployment will create
interference to the
satellite dish itself. The present techniques create a self-organizing and
self-policing
network of beacon detection components that avoids the need for overprotective
safety
margins, while unlocking significant ¨ and previously unavailable ¨ portions
of the
transmit spectrum for further usage, such as by mobile devices.
[00205] The present systems and methods are further advantageously
applicable to new and developing 5G technologies, and also for frequency
ranges both
above and below the spectral bands described herein by way of example. For
example, the
embodiments described above for microwave point-to-point link protection may
be
implemented along lines similar to those described herein with respect to cm-
and mm-
Wave 5G frequencies. However, since 5G beam transmissions are steerable to the
direction of the receiver (which can move), in an exemplary embodiment, the
present
beacon detector is configured such that the beacon detector is able to scan
360 degrees. In
this example, each individual operator may be assigned different bands, and
thus it is very
important to monitor the adjacent channel interference. Where operators share
the same
spectrum, protection will more closely follow the microwave point-to-point
embodiment of
FIG. 10.
[00206] The central server of the present embodiments may be, for
example, implemented within the context of current CBRS band infrastructures,
as
described above, where multiple SAS operators share information with regard to
their
registers users (e.g., APs) such that each SAS operator may individually
perform the
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calculations needed to prevent interference. According to this current model,
all SAS
servers are considered equal, and there is no master server. The present
embodiments
though, enable a master server to be optionally designated. The present
embodiments are
further advantageously capable of realizing, in the case of a single operator,
the
deployment of a plurality of central servers in a cloud architecture in order
to improve
calculation speed, scalability and residence. In the exemplary embodiment, a
master server
for the infrastructure is designated to maximize such improvements.
UE INTERFERENCE MANAGEMENT AND SPECTRAL FREQUENCY REUSE
[00207] In the embodiments described above, although some of the
registered FSS sites in the 3.7-4.2 GHz band may not be in use, the total
number of these
registered sites is nevertheless likely to exceed the number operating within
the 3.55-3.7
GHz spectrum by at least two orders of magnitude. As described above, the CBRS
band is
considered manageable due to the relatively small number of FSS sites, whereas
the 3.7-4.2
GHz band includes over 4700 registered FSS sites, and possibly as many or more
unregistered FSS sites.
[00208] Signal path loss to a specific point within a cell is determined in
consideration of a number of factors, including transmission, environment, and
losses due
to multiple signal paths (multipath) causing self-destructive interference. At
locations
within an FSS coverage area transmission modeling may be utilized to predict
the available
power from the antenna with respect to interference. As used herein,
"coverage" refers to
the geographic area around the FSS site where interference from terrestrial
radio
transmitters may cause interference. In general, the amount of power at the
antenna output
is a function of the amount of power provided to the antenna, as well as the
antenna radio
frequency radiation pattern. This power output and antenna gain is sometimes
referred to
as Effective Radiated Power (ERP) or, if referenced to an Isotopic antenna,
the Equivalent
Isotropically Radiated Power (EIRP), which is the product of transmitter power
and the
antenna gain in a given direction relative to an isotropic antenna of a radio
transmitter. The
EMI? is typically listed in dBi (decibels over isotropic), and enables the
conventional
determination of signal strength along various radials from the antenna.
Other
conventional techniques are known for calculating the ideal transmission loss
utilizing
transmitter power output, transmission cable loss, antenna gain, free space
propagation
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loss, and antenna and receiver gain. However, such conventional techniques are
only able
to predict a theoretical, best case scenario for coverage.
[00209] Another conventional technique is known as environment
modeling, which is used to determine the effect of terrain features between
the cell site and
a specific position within the cell. In conventional parlance, the term
"environment" refers
to these terrain features, and not to actual weather conditions such as
humidity,
precipitation, temperature, etc. In general, the signal path losses
attributable to dispersion
will increase as the inverse square of the distance from the cell site
increases, however,
environment factors can greatly affect these losses. Environment modeling
considers the
signal reduction due to the distance from an AP site, as well as diffraction
losses caused by
buildings or other terrain features between the cell site and the specific
point within the
cell. Furthermore, since radio propagation conditions vary significantly in
typical
operating environments, signal path loss models are known to account for the
statistical
variability of the received signal (e.g., environmental shadowing) by
incorporating suitable
power margins/offsets for the purpose of system planning. Nevertheless, as
described
above with respect to FIG. 1, such conventional modeling techniques still
require highly
conservative planning schemes that do not consider the actual conditions of
the particular
environment for the cell/AP site.
[00210] A third conventional modeling technique is used to predict the
effect from multiple signal paths, and the resultant destructive interference
therefrom, at the
received location, i.e., multi-path fading. Multi-path fading results from
multiple paths
taken by a signal from the cell site to a specific point within a cell.
Specifically, when two
or more signal components arrive at a particular reception point in space
after traveling
different distances, the received signals from these different paths may no
longer be in
phase. Accordingly, when these different signals are reunited, the difference
in their
respective phase shifts may combine in a destructive manner, and produce a
degraded sum
signal at the specific point of interest. Thus, it is not possible in practice
to achieve
precision modeling of destructive interference because of the number of
variables involved,
their associated parameter accuracy, and the relatively short (e.g., 7.1 to
8.3 cm)
wavelengths used by the FSS services (e.g., 3.6 to 4.2 GHz). Therefore, for
system
planning purposes, conventional multi-path modeling techniques typically
include power
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margins/offsets in the path loss predictions to account for the effects of
multi-path fading,
and such statistical modelling is highly dependent on the environment. Similar
to the other
conventional modeling techniques, such margins/offsets typically require
overly
conservative predictive values.
[00211] Furthermore, when determining the signal path loss from the FSS
site to a specific point, where an AP may be placed, under one or more of
these
conventional techniques, conventional signal path loss equations for cellular
service
communications must also be calibrated to accurately model the specific area
around the
FSS site. However, because the specific area around the FSS site might
typically extend
over tens of kilometers for consideration of interference with placement of
potential
interfering antenna at clutter or below clutter, such calibration is
particularly challenging in
practice and still require conservative protection margins. Conventional
calibration
techniques are known to calculate values for geographical environment
parameters, in
order to account for such factors as urban, suburban, and/or rural morphology,
height
differences between the transmitter and the remote receiver, and the density
and height of
terrain features between these two respective antennas. As described above,
obtaining this
information is expensive, and the information that is obtained is still
subject to change
according to changes in the terrain (i.e., buildings built/demolished, trees
leafing in the
spring, shedding in the fall, etc.). Seasonal foliage changes can have a
significant impact
upon signals in the 3.6-4.2 GI-[z downlink frequency range.
[00212] Effective interference planning thus requires the use of suitable
models to adequately predict interference, but the conventional models
described above are
semi-deterministic or empirical, and therefore must be calibrated to the
specific
environments in which they are implemented, which involves modifying the
particular
model parameters to approximate the relevant measurement data. Some
conventional
propagation models include geographical parameters such as whether the
environment is
rural or urban, the ground height relative to the transmitter, and the terrain
between the
transmitter and receiver. In the conventional techniques, such environment
information
may be obtained from a source such as the Geographical Information System
(GIS), but
this information is not obtained in real time.
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[00213] Conventional modeling techniques also do not sufficiently
consider the interference effect from mobile UEs to the FSS site. Although an
individual
UE may transmit an ElRP that is an order of magnitude lower than that of a
fixed AP (see
Table 2, below), the density of multiple UEs with in the area of interest may
often be at
least an order of magnitude greater than the density of APs within the same
area, and
therefore the effect of multiple UEs may be as significant as, or greater
than, an individual
AP, and the UEs are likely to be more evenly distributed over the area than
the APs.
Moreover, because the UEs are mobile, and will often move locations around the
terrain,
the resultant interference effects from the UEs may abruptly change, for
example in the
case of a UE emerging from the shadowing effect of a building to obtain a
direct line of
sight to the FSS. Thus, the conventional modeling techniques described above,
which are
not based upon real-time measurements, are particularly limited in their
ability to
accurately predict interference to the FSS.
[00214] Through further development of the embodiments described
above though, the real time measurement capabilities offered by the beacon-
based
infrastructure overcome these challenges presented by the conventional
modeling
techniques. The systems and methods described herein able to obtain (e.g.,
through
implementation at the central server) a more accurate interference
determination by first
reasonably assuming that particular APs sharing the spectrum are at fixed
points. Once the
propagation loss between an AP and the FSS site has been established
(described above)
the server is able to assume that this established propagation loss of value
is unlikely to
rapidly change. However, in some instances, it may be impractical to utilize
only the real-
time beacon transmissions to determine the UE effects due to such
considerations as (i) the
considerable number of UEs that may be present within a selected area, (ii)
the variable
range of speed at which the mobile UE might be traveling (e.g., 0 km per hour
(kph) for a
stationary UE, up to 130 kph for a UE traveling in an automobile on the
highway), and (iii)
variable shadowing effects as a UE comes within range of taller or shorter
buildings. That
is, in some embodiments, beacon transmissions may be implemented at the UE
level, in
other embodiments, other parameters may be more practical to determine the UE
effects on
the FSS site.
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[00215] Table 2, below, lists the CBRS (i.e., 3.55-3.7 GHz) EIRP
transmitter powers according to device classification. As can be seen from
Table 2, the
EIRP of the typical UE device is considerably lower than the EIRP values of
the several
APs, namely, by an order of magnitude or more. Nevertheless, because the
number of UEs
that may be present within a given area around the FSS site may be an order of
magnitude
or greater than that of the number of APs, the following embodiments implement
techniques for spectrum re-use and HE management around an FSS site.
TABLE 2
Device Classification dBm dBm/MHz
AP ¨ Category B: Rural 47 37
AP ¨ Non-Rural 40 30
AP ¨ Category A 30 20
UE ¨ End User 23 13
Spectrum Re-use
[00216] FIG. 11A depicts an exemplary protection zone layering scheme
1100 for an FSS site 1102. FSS site 1102 is surrounded by a first area zone
1104, a second
area zone 1106, and a third area zone 1108. First area zone 1104 is smaller
than, and
encompassed entirely within, second area zone 1106, and second area zone 1106
is smaller
than, and encompassed entirely within, third area zone 1108. For purposes of
this
explanation, second area zone 1106 excludes first area zone 1104, and third
area zone 1108
excludes second area zone 1106 and first area zone 1104.
[00217] FIG. 11B illustrates a data table 1110 for calculating
the
respective parameters of area zones 1104, 1106, and 1108 according to scheme
1100, FIG.
11A. In the exemplary embodiment, data table 1110 is implemented to calculate
zones of
spectral use, with satellite gain profile, for the several device
classifications shown above
in Table 2 distributed radially around the FSS. In some embodiments,
calculations
according to data table 1110 are further implemented for adjacent channels and
co-channel
interference. Data table 1110 depicts values for minimum link budgets, as well
as safe
responding distances, regarding examples of a single interference source
having the
respective transmitter powers shown for the three different APs listed in
Table 2. In the
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exemplary embodiment, data table 1110 includes calculated values based on
measurements
regarding a propagation model for a residential morphology, having transmitter
antennas
deployed below clutter (e.g., 20 m), and developed for 3.5 GHz. An AP
operating in one
of area zones 1104, 1106, 1108, may be limited to an amount of allowable power
and/or
available spectrum.
[00218] As illustrated in data table 1110, the calculated values assume a
maximum interference value (e.g., noise input) of -129 dBm/MHz at the
satellite antenna
waveguide for co-channel, and includes defined limits for the first adjacent
channel and
second adjacent channel. As illustrated in FIG. 11B, higher limits for the
first adjacent
channel and the second adjacent channel take advantage of the out of band
emission limits
of 40 and 52 dB, respectively. In the particular environment measured to
obtain the
exemplary values illustrated in data table 1110, it is expected that higher
safety distances
would be yielded over the -60 dBm aggregate LNB blocking limit. The
calculations
illustrated in FIG. 11B are further shown with respect to the relative
satellite antenna
elevation(s) to satellite(s) in geostationary orbit. From the exemplary values
shown in data
table 1110, it can be seen that, at a measured elevation of approximately 35
degrees, -6.6
dBi of antenna gain is experienced from the terrestrial interference source.
However, at 5
degree elevation, further north of this measurement location, the interference
source would
experience 14.5 dBi of gain.
[00219] According to scheme 1100 and data table 1110, therefore, the link
budget for co-channel may be calculated as being equal to -129dBm/MHz
(representing the
maximum interference value) minus (i) the antenna gain (i.e., as a function of
the
elevation) and the transmitter power (in dBm/MHz). Accordingly, two effective
regions
around the satellite of FSS site 1102 are provided, namely, within the main
beam satellite,
and outside of the main beam.
[00220] In the first effective region, which is within the satellite main
beam, the positive gain profile of the satellite antenna is typically narrow.
For a typical
large satellite dish of several meters diameter, the half power (-3dB)
beamwidth is less than
degrees. However, for ITU interference analysis using a conservative approach,
the gain
profile is assumed to extend over +/- 20 degrees, and this gain profile is
defined according
to: Gain (in dBi) = 32-25*LOG10(in degrees) with 0 dBi at 20 degrees angles
around the
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center (e.g., not taking LNB filter into account). This gain profile equation
thus follows the
envelope of the satellite gain profile, which will have various peaks and
troughs.
Nevertheless, when implemented with respect to the dynamic closed loop the
embodiments
described above, the actual gain of the satellite obtained from real-time
measurements may
be used.
[00221] Data from data table 1110 is taken, for example, from an
exemplary 3.5 GHz transmitter value, and assuming Non-Rural, Cat B Rural, and
Cat A
(e.g., height-limited to 6 m) APs, and a maximum number of end-user devices.
Accordingly, the loss for residential below Clutter may be 15.2+45*LogD, where
D is less
than 200. For values of D greater than 200, the loss may be -53.9+75*LogD. In
this
example, external small cell deployment is assumed to be below Clutter. The
data of data
table 1110 does not assume indoor use, for which the relevant safety margins
would
improve. Additionally, the size of the exclusion area, away from the bore
sight, may be
dominated by -10 dBi, and calculations of LNB may be based on a single source,
and then
distance-modified for an equivalent hundred transmitters.
[00222] Use of such real-time measurements will thus advantageously
enable the present systems and methods to advantageously implement
significantly
narrower gain profiles than what are typically assumed by conventional
techniques. Data
table 1110 thus provides safe distance values from the FSS site for an
interferer, and for
several types of frequency positions with respect to the satellite channel and
the satellite
elevation.
[00223] In the second effective region, which is outside of the satellite
main beam the gain is assumed to be -10 dBi. In the exemplary values shown in
data table
1110, an elevation angle of 48 degrees corresponds to -10dB gain, and thus a
corresponding safe distance may be adequately determined for the radius of
this second
effective region.
[00224] These two effective regions from the antenna around the satellite
of FSS site 1102 thus account for the respective "tear drop" shapes
illustrated for the
respective interference zones represented by first, second, and third area
zones 1104, 1106,
and 1108. The present systems and methods advantageously utilize these
effective regions
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such that portions of the unused spectrum that are not used by FSS 1102 may be
used by
APs that are relatively close to FSS site 1102 in distance.
[00225] In the exemplary embodiment illustrated in FIG. 11A, the
"round" portion of first area zone 1104 has a radius of approximately 150m.
First area
zone 1104 thus represents an exclusion zone within which an AP or UE may not
use any of
the spectrum. First area zone 1104 may therefore be labeled as a "red zone."
Further to
this example, the round portion of second area zone 1106 has a radius of
approximately
300m. Second area zone 1106 thus represents a "yellow zone," within which an
AP may
utilize 288MHz of the available 500MHz of spectrum, and for AP transmitter
powers of
1W (e.g., 30dBm). Similarly, the round portion of the third area zone 1108 has
a radius of
approximately 750m, and third area zone 1108 thus represents a "green zone,"
within
which an AP may utilize the whole of the spectrum, and for AP transmitter
powers of up to
4W. Outside of the green zone/third area zone 1108, the same full spectrum is
available for
an AP, and for AP transmitter powers of up to 50W The exemplary embodiment
illustrated in FIG. 11A is depicted for the use case two different channels.
Other frequency
utilization may yield different frequency availability.
[00226] In the example illustrated in FIG. 11A, these exemplary values
were calculated under particular conditions. In actual practice of the these
techniques, the
central server may be configured to determine the actual power, spectrum, etc.
and
dynamically adjust such operating parameter to reflect changes to the
utilization of the
spectrum, the arrangement or number of APs (and also their associated UEs, or
other
significant changes to the environment.
[00227] The determination of these areas is calculated by the central
server (SAS). They would be dynamic. For example, the available spectrum
outside the red
zone would be a function of the utilization of channels by the FSS. As it uses
more
channels less is available in yellow zone. Also, should the propagation
environment change
then the size of the zones can be re-calculated. This would influence the
handover zones
coordinated by the central server and the EPC. If interference was detected,
then the safety
zones could be increased.
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[00228] As demonstrated from scheme 1100, and according to the
exemplary values in data table 1110, the effective operating distances for an
AP near FSS
site 1102 are considerably closer to FSS site 102 than what is conventionally
allowable, or
possible, today (e.g., at present, the co-ordination distance for radio
planning any potential
shared use is 150 km). The amount of spectrum that may be re-used, and the
safe operating
distances thereof, are greatly improved according to these advantageous
techniques, as well
as the closed loop system of the embodiments described above.
Management of UE Interference
[00229] The advantages realized from the present embodiments are even
further increased by the effective management of interference from the UEs.
The present
systems and methods further includes techniques to modify the effective
transmitter EIRP
to represent its own AP EIRP, as well as the sum of all of the individual UE
transmitter
powers associated with the particular AP, for interference calculations to
adequately
represent the effect of UE interference. In this example, the power of the UE
is considered
as a function of the multiple access scheme of the UE, which has a maximum
EIRP value
of 23 dB in CBRS.
[00230] Thus, in the exemplary embodiment, the effective transmitter
EIRP resembles a single point for the interference calculation, with the
single point
representing the AP and its corresponding UE community. This "single point"
assumption
it is justifiably accurate for the approach of this exemplary embodiment,
because the
cellular coverage area radius of the AP is relatively small in comparison with
the much
greater distance of the AP to the FSS site, and because this approach scales
with the power
of the AP itself Accordingly, higher power APs will be to be deployed at
distances further
from the FSS site. In the case of a UE having an EIRP of 23 dBm, associated
with an AP
with a transmitter E1RP of 47 dBm, the potential interference is significantly
more
dominated by the AP EIRP.
[00231] However, this likelihood compares the actual EIRP of the AP
against the EIRP of a single UE. The present embodiments therefore further
consider the
effective transmitter EIRP to additionally reflect, in real-time, the number
of UEs
associated with the particular AP according to their multiple access scheme
type. In some
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embodiments, this number of associated UEs is obtained through the beacon
transmission/measurement techniques described above. In other embodiments, the
number
of UEs is obtained using a fixed line connection from the AP to the central
server, thereby
avoiding the need to transmit a beacon with such information each time there
is a change to
the number of associated UEs, which might occur often for some APs.
[00232] In at least one embodiment, the central server is configured to
protect the FSS site by assuming a predetermined, or pre-loaded, number of UE
devices
associated with each class of AP. In this example, the pre-loaded number of UE
devices
represents a loading for the effective coverage areas of the differing types
of transmitter.
For example, more UEs may be associated with a Class B AP transmitter than
might be
associated with a Class A AP transmitter. Accordingly, if=the number of UE
devices
actually associated with the AP is lower than the pre-loaded value, then no
reporting of
changes would be required from the AP. In such circumstances, the AP may be
configured
to only report the associated UE number to the central server when the pre-
loaded number
is exceeded, thereby advantageously reducing and/or minimizing the signaling
across the
system.
[00233] In some instances, the variance of UE power associated with a
shadow effect may be assumed to be relatively small in consideration of the
safety margins
described above, such as in the case of APs located a significant distance
from the FSS.
Nevertheless, in an exemplary embodiment, the central server is further
configured to
provide an estimate from its particular propagation model to represent a
maximum likely
value of the shadow effect. This maximum likely value is of particular utility
with respect
to APs near FSS site 1102 in the yellow zone/second area zone 1106 outside of
first area
zone 1104 (the exclusion zone/red zone). Similarly, the central server may
also be
configured to estimate any significant multipath effects from the underlying
propagation
model, that is, which has been self-calibrated by registration of the
respective beacons
according to the systems and methods described above. Accordingly, in the case
where
shared use of the selected spectral band permits carrier aggregation with the
CBRS band,
the present systems and methods will further advantageously enable development
of APs
that support the whole of the aggregated band.
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[00234] FIG. 12 is a schematic illustration of a shared use system 1200
within the exclusion zone (i.e., first area zone 1104) around FSS site 1102,
FIG. 11A. In
the exemplary embodiment, system 1200 includes a central server 1202 (e.g., an
SAS), a
plurality of beacon-equipped APs 1204, with each AP 1204 having associated
there with
one or more UEs 1206. In the exemplary embodiment, system 1200 further
includes a
mobile core network 1208, which may represent an Evolved Packet Core (EPC) of
a Long
Term Evolution (LTE) network.
[00235] In exemplary operation of system 1200, contiguous service to the
UEs 1206 may be provided even within the satellite exclusion zone of first
area zone 1104
through implementation of a handover 1210 to one of the umbrella CBRS bands,
or
alternatively, another one of the mobile spectrum bands under the control of
core network
1208. If, for example, a portion of the C-band is re-allocated for mobile use
(e.g., the
lower 200 MHz), while the remaining portion (e.g., upper 300 MHz) is retained
for satellite
use, the coexistence systems and methods described herein are fully applicable
to enabling
a handover to this re-allocated spectral portion where interference is
detected. The
principles of the present embodiments though, are not limited to this specific
re-allocation
case, or the particular spectral division even within this exemplary case. In
the exemplary
embodiment, handover 1210 is accomplished through utilization of a link 1212
between
central server 1202 and core network 1208. In one example, handover 1210 may
be
triggered when a particular UE 1206(2), associated with AP 1204(2), comes
within a
defined distance from FSS site 1102. Further to this example, outside of the
exclusion
zone of first area zone 1104, association and use the given spectrum (e.g., C-
band, etc.)
may be implemented when in range of a small cell.
[00236] According to an exemplary embodiment of system 1200, central
server 1202 may be further configured to permit no spectral band registration
within the
exclusion zone of the first area zone 1104 as the AP registration process will
include the
geographical coordinates of the AP. Under this embodiment, APs within the
exclusion zone
of a 3.7-4.2 satellite FSS may cover the whole 3.55-4.2 GHz spectrum, but only
the 3.55-
3.69 GHz spectrum would actually be available. In this example, the 10MHz of
spectrum
from 3.69-3.7 GHz is withheld from availability to represent a guard band. In
the case
where no guard band might be required, this additional 10 M_Hz might also be
made
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available. In an alternative embodiment, the macrocell of a Mobile Network
Operator
(MNO) is utilized.
[00237] According to the advantageous systems and methods described
further herein, a more effective and accurate means is provided to represent
the effects of
UE-based interference on an FSS site, and particularly with respect to the
particular
spectral band and a UE associated with an individual AP. Such representative
means is
distinguishable over conventional techniques, and that it reflects the actual
number of UEs
associated with an AP in real-time, and further enables an accurate estimate
of the
statistical variation of the UE interference due to shadowing effects.
[00238] The present embodiments further advantageously enable the
creation of a strict exclusion zone around an FSS site for protection, while
still allowing
TIE use of CBRS and macro-cellular spectrum within the exclusion zone. The
present
embodiments further provide a series of zones outside of the exclusion zone
(two such
additional zones described herein, but more could be realized within the scope
of this
disclosure), which increasing allow the use of the band spectrum at greater
distances, and
for higher transmitter powers. According to the exemplary principles described
herein,
contiguous UE service across is realized within the vicinity of an FSS site,
and up to the
location of the FSS site itself through use of a handover (e.g., with an EPC).
This handover
is further enabled by providing a new communications link between the EPC in
the central
server. The dynamic nature of these zones thus reflects the changes in FSS
channel
utilization, as well as changes in the environment.
[00239] The central server according to the present embodiments may be
further advantageously configured to enable the combination of the CBRS
spectrum (3.55-
3.7 GHz) and the C-band spectrum (3.7-4.2 GHz), etc., within an AP, as well as
the
development of APs that more effectively utilize this combined spectrum. The
central
server may be further configured to prevent AP registration within the
exclusion zone,
while additionally being able to obtain the location of a given AP based on
broadcast or
hard link signal of a GPS location, or according to the other beacon
transmission/detection
techniques described above.
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UE Beacons
[00240] As described above, the beacon infrastructure and techniques of
the present embodiments are applicable to UEs, in addition to APs. Although,
due to the
vast number of UEs operating throughout the country, as well as the additional
cost
involved in extending the beacon infrastructure to the UEs and the related
reduction in
transmitter power that effectively reduces the link budget (and thus the
system detection
range), it might not always be practical to extend the infrastructure to all
UEs.
[00241] Nevertheless, it is useful to enable the UEs to emit their own
transmitter beacon in the case where the relevant AP or APs is/are close in
proximity to the
FSS site where the variance of the effects of the HE transmitter power would
be more
difficult to model or require overly conservatively protection limits. In an
exemplary
embodiment, a HE beacon may be provided using a client on the UE device or
within its
operating system, which is instructed to operate according to the central
server. It may be
assumed that such devices are close in proximity to the FSS site, however, the
issue of
limited link budget would not be a significant concern because the close-
proximity of UE
devices and also because this number may be considered to be relatively small.
[00242] Additionally, the use of IJE beacons may be advantageously
limited to be performed only, for example, during a training or calibration
phase, and not as
a continuous operation. That is, in this example, during an initial
calibration phase, the UE
beacons associated with a particular AP may be measured at different locations
around the
AP with which they are associated. These UE beacon measurements, together with
the
measurement of the AP beacon, may then be used to determine the effective AP
transmitter
power and its statistical distribution to represent the whole interference
effect as a single
point as function of the number of UEs, namely, the effective EIRP of the AP.
Over time,
central server may be configured to develop a detailed statistical model for
the AP and the
number of UEs associated there with. This statistical model may then be used
to determine
the safe transmitter power of APs in close proximity to the FSS site, for
example, up to 500
m.
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[00243] The central server may be further configured to dynamically
reduce the allowed transmitter power of the AP by taking into account the
shadowing
effects of buildings within the area experienced by UEs. By accounting for the
shadowing
effects, the operation of the system is further enabled to directly reduce the
AP
interference, while also reducing the size of the coverage area of the AP, and
thus the
number of UEs that will likely be supported by the AP. In some instances, the
central
server may be configured to subtract the shadow effect of buildings on the
edges of a
particular area where the relevant UEs good instead be supported by a CBRS or
macrocell,
thereby rendering the total effect of the APs and associated UEs significantly
more
deterministic.
[00244] FIG. 12A is a schematic illustration of shared use system 1200,
FIG. 12, with respect to all three area zones (i.e., first area zone 1104,
second area zone
1106, and third area zone 1108) around FSS site 1102, FIG. 11A. In this
exemplary
embodiment, system 1200 further includes at least one beacon detector 1214
within
exclusion zone 1104, which has a fixed connection 1216 to central server 1202.
In this
exemplary embodiment, respective UEs 1206 include a UE beacon transmitter
1218, and
measurement of the beacons transmitted from one or more beacon transmitters
1218 is
performed by beacon detector 1214. The data measured from the received beacons
may be
then relayed to central server 1202 over fixed connection 1216. In other
embodiments, a
wireless link may be used where a fixed link is not available.
[00245] FIG. 12A thus illustrates a multi-zone operational distribution of
UEs 1206 around FSS site 1102. In the exemplary embodiment, central server
1202
manages potential interference by preventing any of UEs 1206 or APs 1204 from
broadcasting within innermost exclusion zone 1104 (red zone). In further
operation the
exemplary embodiment, system 1200 permits UEs 1206 within second area zone
1106 (i.e.,
UEs 1204(1), 1204(2), 1204(4), 1204(5) in the yellow zone), exploitation of
the available
spectrum, at reduced transmitter power(s). Outside of second area zone 1106,
within third
area zone 1108 (green zone), central server 1202 is configured to allow
further spectrum
availability, and at higher transmitter powers (e.g., UE 1206(6)). High
propagation loss
over distance from FSS site 1102 thus contributes to the additional spectrum
availability
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and higher transmitter power in third area zone 1108. Beyond third area zone
1108, UEs
1206 operate in a conventional fashion (e.g., UE 1206(7)).
[00246] The examples described above are discussed with respect to UEs
at distances of less than approximately 500 m from the FSS site. In the
exemplary
embodiment, at distances greater than 500 m, the effect of UEs 1206 may be
alternatively
modeled using the effective EIRP, which represents the AP transmitter power,
and also
considers the additional effect of the number and type of UEs associated with
the particular
AP. Under 500 m, such modeling techniques would not be expected to be as
accurate due
to the difficulty in modeling the effect of UEs 1206 as a single point source
of interference
coincident with the AP position due to the propagation variation associated
with UE
movement, Thus, in system 1200, UEs 1206 are configured to transmit a beacon
from
respective UE beacon transmitters 1218, when instructed by central server
1202, such that
beacon detector 1214 is able to detect the transmitted beacon by measuring the
received
power against the position of the UE 1206 transmitting the beacon.
[00247] In an alternative embodiment, an exclusion zone of 500 m around
the FSS is created, and in which central server 1202 permits no UE to operate
using the
3.7-4.2 GHz spectrum. At distances of 500 m and greater, the UE may then be
permitted to
operate using the effective AP power. This alternative may be useful in the
case where the
system might more optimally determine that risk of interference is outweighed
by the
operational cost (e.g., power, computational requirements, etc.) of having the
UEs transmit
their on beacons, and the associated modeling computations that arise
therefrom.
[00248] Similar to the embodiments described above, in the exemplary
embodiment, the transmitted beacon includes the ID of the particular UE 1206,
its
transmitted power, and its GPS location/position. Through such measurements,
central
server 1202 is able to collect detailed measurements of the plurality of UEs
1206 associated
with respective APs 1204, and dynamically model the interference management
therefrom.
In some embodiments, beacon detector 1214 is alternatively, or additionally,
in
communication with central server 1202 over a communication link other than
fixed
connection 1216.
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[00249] The interactive functionality of central server 1202 with EPC
1208 thus enables handovers 1210(1), 1210(2), 1210(3) from the associated
spectrum (e.g.,
including the C-band), to either the CBRS or mobile network macrocells.
Accordingly,
any interference to FSS site 1102 from UEs 1206 may be avoided by locating the
UE
broadcast within other spectrum bands or C-band guard bands. In an embodiment,
central
server 1202 is configured to initiate and sequence the beacon transmission
from both APs
1204 and respective associated UEs 1206. According to this exemplary multiple
access
scheme, the signaling load on system 1200, as well as the computational load
on central
server 1202, is significantly reduced, and conflicts are further
advantageously avoided.
[00250] Through the collection of measured beacon transmissions from
the several UE beacon transmitters 1218, a detailed coverage map of one or
more APs 1204
may be built, dynamically and in real-time. Dynamically because these models
can be
updated from time to time to take into effect any environmental changes. This
coverage
map thus represents an effective means of representing the AP transmitter
power, with an
effective E1RP that reflects a sum of the individual respective UE transmitter
powers
associated with that AP 1204, as well as the type of individual UE 1206, and
the associated
variance of different UE positions. In an exemplary embodiment, central server
1202 is
further configured to calculate a statistical distribution of respective UEs
1206, and utilize
this statistical distribution within an optimization algorithm for protection
of FSS site 1102.
[00251] FIG. 12B is an overhead view of a partial schematic illustration of
a corner effect 1220. In the exemplary embodiment illustrated in FIG. 12B,
corner effect
1220 is depicted with respect to a presence of the buildings 1222 disposed
between one or
more UEs 1206, FIG. 12-12A, and FSS site 1102. In this example, building 1222
is
disposed along a first direct path 1224 between UE 1206 and FSS site 1102 at
an initial
position of UE 1206. As LIE 1206 moves in a direction 1226, a second direct
path 1228,
between UE 1206' and FSS site 1102, is unblocked by buildings 1222. That is,
movement
of the UE 1206, from "behind" building 1222, and into a direct line of sight
as UE 1206',
can lead to a dramatic increase in the potential interference to FSS site 1102
when UE
1206' is in close proximity to FSS site 1102, in comparison with HE 1206
behind building
1222.
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[00252] FIG. 12C is a partial schematic illustration of a hotspot effect
1230. In the exemplary embodiment illustrated in FIG. 12C, hotspot effect 1230
is
depicted with respect to handover 1210 in the vicinity of a hotspot 1232, and
with respect
to first area zone 1104 and second area zone 1106. More specifically, where
there is
unacceptably high signal strength from a particular UE 1206 to FSS site 1102,
i.e., at
beacon detector 1214, central server 1202 may be configured to coordinate with
EPC 1208
to cause handover 1210. This region of unacceptably high signal strength thus
creates
hotspot 1232. In the exemplary embodiment, central server 1202 is further
configured to
identify such hotspots 1232 of potential interference during an initial
calibration phase. In
the case where hotspots 1232 identified during initial calibration, hotspot
identification
need not be a continual or ongoing operation of central server 1202. In some
embodiments, central server 1202 may be configured to perform hotspot
identification
periodically, continually, or upon measurement of an environmental change.
According to
this advantageous embodiment, central server 1202 is further able to managing
potential
interference by directing APs 1204 or UEs 1206 to avoid hotspots 1232.
[00253] Similar to the embodiments described above, in the examples
depicted in figs 12-12C, the resulting propagation loss and lower UE
transmitter powers
may be considered to have a negligible effect outside of distances
approximately 500 m
away from FSS site 1102. The 500 m threshold in this example though, is
discussed by
way of example, and not in a limiting manner. As described above, transmitter
power and
the respective radii of area zones 1104, 1106, 1108 may vary. However,
according to the
several embodiments depicted in FIGS. 12-12C, central server 1202 is able to
dynamically
adjust the size of the respective area zones according to the dynamic
measurements that are
collected in real-time. System 1200 is thus able to further consider the
relative distances
and powers of APs 1204 from FSS site 1102. That is, as relatively high-power
APs 1204
are located distances far from FSS site 1102, the contribution of UEs 1206
associated with
that high-power AP 1204 is considered to be relatively small in comparison to
the much
stronger AP power.
SELF-CALIBRATING PROPAGATION MODELS
[00254] Several conventional techniques utilize empirical propagation
models to determine FSS interference from other APs and mobile UEs for shared
spectrum
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use and/or realization of the maximum commodity of the spectrum. One such
conventional
technique simulates wireless information transport systems using time and
frequency
dynamic effects on stationary and mobile systems. The technique employs
several
modules in a distributed interactive simulation structure to provide a real-
time simulation
output signal that is adjusted by voice and data inputs. Another conventional
technique
utilizes a computer implemented modeling tool for cellular systems that
predicts signal
strength in consideration of terrain effects and the presence of man-made
structures. This
conventional technique predictively models under the line of sight conditions,
similar to the
highly conservative propagation tools described above with respect to FIG. 1.
[00255] A third conventional technique performs interference studies in a
two-step process, which first analyzes all potentially interfering systems to
exclude systems
that can be determined to not be causing interference, and second, performs a
more detailed
analysis on the remaining systems that cannot be excluded in the first step.
This technique
utilizes pre-calculated average terrain and roughness values, and substitutes
an effective
antenna height for the actual antenna height in its propagation loss
calculations. A fourth
conventional technique models radio field strength for cellular site coverage
by automating
sampling procedures, collecting data at various monitoring points, and
interpolating the
collected samples/data. An iterative approach is used to mitigate calibration
errors, but
conventional technique requires the introduction of noise into the data
analysis to avoid
convergence on a local minimum.
[00256] Accordingly, each of these conventional empirical propagation
modeling techniques produce significant inaccuracies from the assumptions that
are
required in the respective model. Furthermore, calibration of these
conventional empirical
tools is expensive, and also particularly challenging for determining the
interference to an
FSS site from other APs/UEs for shared spectrum use. The following embodiments
therefore further expand upon the innovative MBP model and beacon-based
systems and
methods described above. More particularly, the embodiments described further
herein
provide a more accurate and inexpensive self-calibrating propagation model is
provided
[00257] Referring back to FIG. 4, transmit frequencies and power levels
may be authorized for an AP based upon a measured path loss, or on a
calculation of the
loss between the AP and the FSS site. In both instances, a propagation model
may be
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implemented to calculate the respective loss. The present embodiments
therefore derive a
propagation model that overcomes the weaknesses of the conventional empirical
propagation models described above. The exemplary propagation model described
herein
avoids the inaccuracies associated with the empirical models, and also the
expense of
calibrating the empirical models to achieve maximum commodity of the spectrum.
The
present propagation model embodiments represent significant improvements over
the
conventional models that are unable to determine from individual measurements
the signal
strength at every point within the cell, such that cell coverage can be
confirmed, and
problem locations can be identified and addressed. The improved modeling
techniques
herein allow cellular service providers, for example, to more optimally
determine an initial
cell site location, the optimum placement of additional cell sites, frequency
planning, and
required power levels at specific sites.
[00258] In the exemplary embodiment, modeling of the environment
further considers the reduction of the signal caused by the distance from a
cell site, as well
as diffraction losses caused by buildings or other terrain features between
the cell site and
the specific point within the cell. Such considerations are determined in real
time from the
MBP scheme described above, and therefore represent still further improvements
over
conventional techniques, which are unable to accurately track the variance of
radio
propagation conditions that will inevitably occur in the typical operating
environment. As
described above, conventional signal path loss models are only known to
account for the
statistical variability of the received signal (e.g., environmental shadowing)
by
incorporating suitable power margins/offset calculations for system planning
purposes.
[00259] In an exemplary embodiment, a propagation modeling scheme
utilizes radio beacons to further implement MBP: (i) as part of the overall
system that
protects against/prevents interference to the FSS site from the introduction
and service of
an AP/RAP sharing the same spectrum; and (ii) to develop a self-calibrating,
"learning,"
propagation model that becomes increasingly more accurate over time, such that
the model
substantially reflects the actual dynamic environment conditions in the
system. In the
exemplary embodiment, such self-calibration capability is automatic, and does
not require
(human) operator direction or intervention for cellular planning.
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[00260] In some embodiments, utilization of the present propagation
model may not be considered to play a significant role with respect to
interference
prevention. In other embodiments, as described above, the dynamic and closed
loop nature
of the propagation model is significantly advantageous to mitigate
interference effects.
Nevertheless, in either case, the exemplary propagation model described herein
is
particularly advantageous with regard to the planning of optimum coverage and
capacity in
the design and evolution of APs for a service provider. The present self-
calibrating
propagation model is further useful to identify "hot spot" regions of
potential interference,
which are conventionally known to be chaotic and unpredictable. The present
propagation
model still further is useful to identify areas where the multipath effect is
significant; the
present model enables the central server to accurately estimate the multipath
effect for
interference migration.
[00261] The propagation model described herein further avoids the
problems encountered through implementation of the conventional empirical
models, but
without sacrificing some useful capabilities of the empirical models. That is,
the present
propagation model is advantageously scalable, and may be configured to enable
to include
additional margins built into the system model to address potential
interference that night
not to be fully addressed by measurements only. For ease of explanation, the
embodiments
below are described with respect to one particular example in which operation
of the
system is based on a requirement to achieve a beacon link budget of at least
200 dB
(satellite elevation of 5 degrees with a significant number of APs). Although
different link
budgets and other parameters are well within the scope of this application,
the examples
below are illustrative to demonstrate the detection of distance co-channel
interference from
multiple sources. Such multiple source detection may be achieved, for example,
through
transmission and detection of the unique ID of the AP (e.g., to minimize
bandwidth usage,
described above), or according to one or more complex detection schemes
designed with
respect to IoT applications.
[00262] FIG. 13 is a schematic illustration of a shared use system 1300
that implements an MBP scheme for a self-calibrating propagation model. In the
exemplary embodiment, system 1300 includes a central server 1302 (e.g., an
SAS) for
managing interference to a plurality of FSS sites 1304 (four such FSS sites
shown in this
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example, 1304(A)-1304(D))). In this example, each FSS site 1304 operates
within a
respective terrain region 1306, and each FSS site 1304 is equipped with at
least one
respective beacon receiver 1308 in operable communication with central server
1302. A
system 1300 further includes a plurality of beacon transmitter-equipped
existing APs 1310
distributed among the plurality of terrain regions 1306. As illustrated in
FIG. 13, an
individual one of the respective terrain regions 1306 may overlap with one or
more other
terrain regions 1306.
[00263] In exemplary operation of system 1300, each of beacon receivers
1308 records the signal strength of a beacon transmission detected from one or
more
existing APs 1310, similar to the embodiments described above. In at least one
embodiment of system 1300, one or more of beacon receivers 1308 is further
configured
for direct connection to central server 1302, and dynamically informs central
server 1302
of the operating conditions (e.g., channel of operation, location, pointing
direction, etc.) of
the respective FSS site 1304.
[00264] In further exemplary operation of system 1300, a beacon
transmitter-equipped new AP 1312 is introduced and seeks transmit
authorization from
central server 1302, similar to the operation of system 500, FIG. 5. In this
example, new
AP 1312 is located within an overlapping region 1314 that extends across
portions of each
of terrain regions 1306(A), 1306(B), and 1306(C). Introduction of new AP 1312
into
system 1300 may, for example, be performed in a manner similar to process 600,
FIG. 6,
such that new AP 1312 may share the same C-band spectrum, within overlapping
region
1314, as FSS site 1304(A), FSS site 1304(B), and FSS site 1304(C). In the
exemplary
embodiment, the self-calibrating propagation model of system 1300 is
implemented by
central server 1302 within step 606. Process 600 otherwise may be implemented
in a
manner similar to that described above with respect to FIG. 6.
[00265] That is, central server 1302 of system 1300 is configured to
implement step 614 such that new AP 1312 AP transmits a beacon which is
detected by
beacon receivers 1308(A), 1308(B), and 1308(C). In the exemplary embodiment,
the
detection by the respective beacon receivers 1308 occurs substantially
simultaneously.
Similar to the embodiments described above, the beacon transmitted by the
beacon
transmitter (not separately shown) of new AP 1312 includes the unique ID of
that particular
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transmitter and/or AP, as well as the transmit power of beacon transmitter
itself. In some
embodiments, the beacon transmitter is further configured to transmit location
information
(e.g., GPS data and/or map data in x, y, z co-ordinates), as well as the
number of UEs
associated with new AP 1312, over a fixed communication channel, wirelessly,
or over the
Internet.
[00266] In the exemplary embodiment, information other than the beacon
ID is transmitted over the Internet to maximize efficiency, and thereby
further enhance the
link budget of system 1300 by reducing the overall information content between
beacon
transmitters and receivers. In at least one embodiment, central server 1302 is
further
configured to manage not only potential interference from new AP 1312 to all
FSS sites
1304 encompassing overlapping region 1314, but additionally potential
interference by
UEs (not shown in FIG. 13) associated with new AP 1312 (as well as existing
APs 1310, as
needed) along with consideration of the measured path loss.
[00267] Central server 1302 may, for example, include an SAS, and may
be further configured to calculate the respective three-path loss associated
with the three
separate links (not separately shown) between new AP 1312 and FSS site
1304(A), FSS
site 1304(B), and FSS site 1304(C), respectively, to determine if there is
likely to be
interference, In at least one exemplary operation, FSS site 1304(D) is also
able to detect
the beacon transmitted by new AP 1312, thereby resulting in a four-path loss
calculation. In
this instance, central server 1302 of system 1300 is configured to calculate
four
propagation models, respectively, representing the four different terrain
regions 1306 (in
the example illustrated in FIG. 13) associated with each FSS site 1304. That
is, central
server 1302 manages the introduction of new AP 1312, and the potential
interference
therefrom, according to the four different morphologies.
[00268] In one exemplary morphology of FSS site 1304(D), if the signal
strength of the beacon (i.e., transmitted by new AP 1312) received at beacon
receiver
1308(D) falls below the sensitivity of beacon receiver 1308(D), the beacon
will not be
successfully detected. In such cases, central server 1302 is configured to
determine that
new AP 1312 would not cause interference two FSS site 1304(A). That is,
although the
beacon signal would have fallen below the threshold for detection at 1308(D),
the beacon
may still be detected by other APs, which will have reported such beacon
detection to
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central server 1302. Therefore, central server 1302 will still be able to
verify that the
beacon signal from AP 1312 was originally transmitted.
[00269] In the embodiments described above, the self-calibrating
propagation modeling technique not only serves an important role in the
authorization
process for subsequent transmissions by new AP 1312, the new technique further
provides
valuable information pertaining to the calibration of each of the four
respective propagation
models for each potential communication pathway. Although each of the four
respective
propagation models may be calculated in similar manner as with respect to one
another,
each model will involve different associated parameters.
[00270] Systems and methods according to the exemplary embodiment
depicted in FIG. 13 further advantageously enable the real-time identification
and
remediation of potential interference. That is, although the primary function
of the beacons
described above is to enable MBP, because each potential source of
interference will have
its own unique ID, central server 1302 is enabled to immediately identify and
remedy the
interference by instructing the interfering AP to cease operation and/or use a
different
frequency/transmit power, similar to the remediation steps of process 600,
FIG. 6.
According to the improved configuration of system 1300, such interference may
be
detected and remedied either during the initial installation phase, or during
subsequent
operation. In the exemplary embodiment, beacons are periodically transmitted
according
to a schedule, such that the overall health of system 1300 may be maintained
even as
changes occur to the system environment. In at least one embodiment, central
server 1302
performs regular measurements and calculates statistical variations over short
time periods,
such that further valuable multipath information is advantageously provided to
enhance the
overall interference protection by including a margin for the statistical
variation, separately
from or in addition to specific parameter measurement values.
[00271] Similar to system 400, FIG. 4, system 1300 may also be
configured such that individual beacon transmitters transmit to other
transceivers (e.g.,
beacon detectors, central server, other beacon transmitters having a receiver
component)
within range, and feed the signal strength back to a centralized database of
central server
1302, which thereby significantly enables central server 1302 to train the
propagation tool
to be more effectively self-calibrating. In conventional systems, information
is collected
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by physically driving automotive vehicles equipped with signal measurement
equipment
and GPS technology along the respective signal paths to log into the measured
values.
According to the improved techniques according to system 1300 though, central
server
1302 and beacon receivers 1308 are configured to automatically collect the
measurement
information with each beacon transmission, since the location of each AP is
considered to
be fixed, and the respective beacon ID is recorded upon registration, the new
measurement
information may be recorded without having to recalculate the AP, and by
verifying the
beacon ID using a lookup within the database of central servers 1302.
[00272] Because, in the exemplary embodiment, the beacon transmissions
are transmitted regularly, the self-calibrating propagation model of system
1300 is able to
evolve over time, and thus rapidly represent the true and accurate dynamic
conditions in
each terrain that occur in real time.
[00273] The dynamic self-calibrating features of the present embodiments
further provide the advantageous extension of the beacon infrastructure into a
form of self-
organizing protection (SOP). Specifically, apart from the primary beacon
function for
MBP, the present embodiments further enable the configuration of central
server 1302 such
that the introduction of new AP 1312, or its periodic beacon transmission,
will serve to
additionally measure the transmission loss to existing APs 1310 to yield
further valuable
information useful for network planning, such as FDMA, and for improving the
underlying
self-calibrating propagation model for the whole area of the plurality of
terrain region
1306. According to this advantageous configuration, the MBP capabilities of
the beacon
infrastructure described above are effectively extended to SOP. Whether
directly or
indirectly implemented for FSS protection, the exemplary embodiment of FIG. 13
nevertheless yields considerable information useful for the inexpensive
calibration
underlying self-calibrating propagation model. In some embodiments, the beacon
ID is
transmitted over a dedicated signaling channel. In other embodiments, the
beacon ID is
transmitted over a guard band close to the channel of potential operation.
[00274] In a practical example, system 1300 may include thousands of
existing APs 1310. In such instances, the introduction of a new AP 1312, along
with the
announcement of the beacon/beacon ID associated there with, will yield
potentially
hundreds of measurement data points (or more) at other locations, and
substantially at the
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same time as the corresponding measurements at the relatively fewer FSS sites
1304.
According to this example, existing APs 1310 may be structurally configured to
include an
additional radio receiver dedicated for beacon detection, which may be
specifically tuned
to the relevant beacon signaling channel or guard band. This exemplary
configuration
further allows a main radio of the system (not shown), such as for an LTE
network, to
operate full-time on communication, with the secondary radio on full-time
beacon
detection service. Where only one radio receiver is included, an LTE network
radio might
be disturbed if required to periodically go into a listening mode/pre-planned
listening
mode. According to these advantageous techniques, as the concentration of APs
within
one or more terrain regions could effectively converge the self-calibrating
propagation
model with the regular MBP functioning of central server 1302, since the
transmission loss
vectors between the individual points in space will have already been measured
and
continuously updated. In the case of the system reset, the evolving self-
calibrating
propagation model may be restarted and run until the concentration of APs
increases to a
level to render the propagation model unnecessary.
[00275] In an exemplary embodiment, central server 1302 is further
configured to consider the range of individual beacon transmissions. Referring
back to
FIG. 3A, for an azimuth of 0 degrees, a satellite dish elevation of 5 degrees,
and a satellite
gain of 14.5 dB, the limit for co-channel interference is 180.5 dB with a
single interference
source within the satellite main beam. Accordingly, allowing for higher gain
antennas and
multiple sources, it can be seen that a link budget of at least 200 dB would
be required for
an elevated 5 degree FSS site. In some cases, link budgets of up to 240 dB are
achievable.
However, according to the advantageous embodiments herein, it will not be
necessary to
require significantly greater link budgets, since the amount of additional
interference from
this difference would be considered to be relatively small. Nevertheless, in
at least one
embodiment, central server 1302 may be further configured to include a fixed
penalty in its
interference calculations to account for this relatively small increase in
interference.
[00276] The present systems and methods are further advantageously
capable of considering, within the self-calibrating propagation model,
respective
atmospheric effects encountered by the system, such as troposphere scatter,
which may
results in unpredictable long-range propagation behavior. For purposes of this
discussion,
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"atmospheric" is defined differently from "environmental," as described above.
Atmospheric effects are not only highly unpredictable; such effects also tend
to be very
short-lived. Conventional systems are thus incapable of determining the
atmospheric
effects on the system in real-time. According to the present systems and
methods though,
the MBP capabilities achieved from the beacon infrastructure is further useful
to identify
the source of the AP(s) subject to the atmospheric effects, and then control
the potential
interference resulting from the affected AP(s).
[00277] In the conventional systems, the unpredictability of the potential
atmospheric effects is often cited as a reason for requiring such large
protection zones
around an FSS site. In practice, however, the protection zone requirements are
often
because of the mobile use case, which involve sharing =with macro-cells, which
are
designed to have antennas above clutter, in order to provide longer range
cellular coverage.
Nevertheless, such affects may migrated by the use of small cells below
clutter, which take
advantage of the more hostile propagation conditions. This migration though,
effectively
rules out the shared band use with the respective macro-cellular base
stations, which have
antenna heights above clutter, and hence suffer relatively low propagation
losses to those
antenna below clutter, as illustrated below with respect to FIG. 14 (as
described further
below, small cell use may be realized within the scope of the present systems
and
methods).
[00278] FIG. 14 is a graphical illustration 1400 depicting comparative
data plots 1402 of single-slope and dual-slope models for high density
commercial
morphology-per-clutter classifications. In the example illustrated in FIG. 14,
the path loss
(vertical axis, in dB) is plotted against distance (horizontal axis, in
meters) for both of the
single-slope and dual-slope models, and for both model types below clutter, at
clutter, and
above clutter. As illustrated in FIG, 14, the comparative data plot 1402 are
charted against
a free space path loss plot 1404. In an exemplary embodiment, one or all of
comparative
data plot 1402 and free space path loss plot 1404 are utilized within the self-
calibrating
propagation model described above.
[00279] According to the advantageous techniques described herein, small
cells may therefore be deployed below clutter to share the same spectrum as
the FSS site
using the relevant spectral band. The present embodiments further provide the
self-
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calibrating propagation model that uses a beacon infrastructure to more
accurately measure
the interference contribution from the one or more APs sharing the same band
(e.g., the C-
band) as the FSS site. This new propagation model further enables the central
server
capability to detect environmental changes, and then incorporate those
detected changes
within its calculations to dynamically protect the FSS sites.
[00280] The present systems and methods further enable the capability of
the shared use system, using the unique 1Ds of the separate beacons, to detect
both short
and long-range interference. Using the MBP scheme of such beacon detection,
the system
is further enabled, at the central server, to control the individual APs to
mitigate the
potential interference. The self-calibrating capabilities of the propagation
model further
enables a significantly improved capability for the design and optimization of
AP coverage
and capacity for mobile systems, as well as the measurement of individual
beacon signal
strength to assess the potential multipath effect, and thereby build in
additional parameter
or statistical variation margins for still further interference protection.
The same beacons
may be used for self-organizing protection, and for a learning calibration
model that
automatically improves the accuracy of the propagation modeling over time. The
present
systems and methods are additionally scalable, and may include two separate
radios, with
one such separate radio dedicated for beacon detection.
INCREASED BEACON DETECTION RANGE
[00281] Further to the beacon infrastructure embodiments described
above, it is desirable to increase the range for beacon detection, and
particularly within the
3.55-4.2 GHz CBRS-FSS band, such that potential sources of interference may be
more
optimally detected and managed. That is, the beacon detection range should be
sufficient
to not only detect any source of potential interference, but also to enable
the central server
to better plan the spectrum utilization across the region managed by the
central server. The
greater the range of a beacon, the more APs it will encounter. Each of these
APs may then
be directly managed by the central server to ensure a more efficient global
optimization
solution.
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[00282] The utilization of radio beacons associated with C-band APs (as
well as other spectral transmitters), as described above, enables the
identification of the
beacon transmitter, as well as the detection and the determination of the FSS
interference
contribution from each individual transmitter. However, successful detection
of a beacon
transmission is subject to finite range, or maximum path loss, which is a
significant
consideration. That is, the ability to detect the beacons must achieve a
minimum sufficient
level such that the central server is able to observe all significant
interference, and thereby
implement the closed loop system to manage and control interference to allow
sharing of
the band with both satellite users and other terrestrial radio communications.
[00283] For example, in order to detect transmitters causing potential co-
channel interference, the central server must, under present regulations,
consider distances
up to 150 km from the FSS site. Additionally, the beacon detection systems
described
above should also be capable of determining the effects of aggregation of all
transmitters,
in the entire 500 MHz (e.g., C-band), and up to 40 km from the FSS site. Until
new
operating regulations are adopted, these conservative limits must be addressed
by the
present systems and methods. Nevertheless, it is important to note that the
conservative
limits of the present regulations were defined according to the conventional
techniques,
which did not include the closed loop system of the present embodiments. As
described
above, the present techniques enable significantly lower transmission power
and distance
limits from the FSS site, but without reducing the interference protection to
the site.
[00284] More particularly, for the lowest elevation angle of 5 degrees, and
an Azimuth of 0 degrees, the satellite dish would be assumed to have a gain of
14.5 dB.
For a 1 W transmitter in a 10 MHz bandwidth, the required minimum path loss is
then
180.5 dB for a single co-channel interference source. For high elevation
angles, the
minimum link budget would then be lower than the minimum path loss value, thus
yielding
greater beacon detector ranges. For this example, implementation of WSJT in
the beacon
infrastructure described above will then advantageously allow a maximum path
loss of
198dB at a transmitter power of 1 W with an isotopic antenna. In the case
where
directional antennas are implemented instead of (or in addition to) an
isotropic antenna, the
link budget may be even further extended, as described in greater detail
below.
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[00285] Accordingly, for a one-minute Private Use Area (PUA) 43
transmission, e.g., containing 28 characters sent at 0.5 characters per
second, the
transmission can still be copied down to approximately 27 dB below the level
of receiver
noise. Post-detection averaging can yield nearly another 6 dB improvement in
0.5 hours of
alternating one-minute intervals of WSJT transmission/reception. PUA43 is
cited in this
example because of its decoding capability at low SNR values. Fast detection
using
PUA43, however, requires very accurate alignment of the receiver local
oscillator with the
transmitter. Because the LNB frequency offset may span several kHz, costly GPS
discipline and/or Rubidium based frequency reference techniques are often
further
required. Furthermore, an additional margin of 33dB for WSJT can be quickly
consumed
by an increase in the number of transmitters. It should be noted though, that
the gain of a
satellite dish is typically defined over a relatively small angle, and within
these small
angles that this co-channel considerations are significant.
[00286] According to the innovative systems and methods herein, the
beacon infrastructure advantageously implements a beacon format that (i)
carries necessary
information, such as the unique Radio Access ID used for identification, (ii)
supports
significantly lower SNR values, (iii) is measurable at the receiver, (iv) is
able to utilize
existing receiver systems, or alternatively implement lower-cost transmitters
and receivers,
and (v) supports a multiple access scheme that enables implementation of a
large and/or
scalable number of transmitter beacons. WSJT techniques are described herein
by way of
example, and should not be interpreted in a limiting sense. The present
embodiments may
also implement other modulations schemes, such as WS propagation reporting, or
schemes
used in IoT applications, such as Lora or Ingenu. In Ingenu, for example,
random phase
multiple access scheme has a maximum path loss of 176 dB for 1 Mbit/s signal.
In an
exemplary embodiment, the information requirement for the beacon does not
require such
as high speed, 1Mbit/s, therefore the link budget can be accordingly increased
with a much
lower speed. As described above, some LTE modulation schemes additionally
utilize
Zadoff-Chu (ZC) functions/sequences.
[00287] The present embodiments are thus able to calculate loss for a UE
utilizing LTE as equal to -53.9dB + 75 Log(D) (e.g., D in meters), in a
measured 3.5 GHz
propagation model. In this example, the beacon range is calculated according
to a worst
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case operational scenario, where loss is assumed to be greatest with
increasing distance
below clutter in a residential morphology. According to these assumptions, the
upper limit
of the detection range is calculated to be 2.7 km. In practical applications
though, different
from this example, other morphologies in a typical city environment may yield
detection
ranges of up to 36 km, whereas rural morphologies may yield even greater
detection
ranges. In the case where the infrastructure described herein is implemented
primarily (or
entirely) for small cell use below clutter, the effect of transmitters beyond
a 200-220 dB
maximum path loss is likely to be insignificant with respect to the parameters
described
herein, and therefore these conventional maximum path loss requirements are
significantly
more conservative than would be required according to the present dynamic
closed loop
system. See also Table 3, below.
[00288] In another example, assuming the minimum path loss to be
approximately 180.5 dB for co-channel interference, for a 14.5 dB satellite
gain having a
minimum elevation angle of 5 degrees, 0 degrees Azimuth, and a single 1W
transmitter in a
MHz bandwidth for a single interferer, then a 180.5 dB yield is obtained at a
minimum
distance of 1300 m. Beyond this distance, a single interferer would
increasingly contribute
less than the present FCC interference limit, that is, as the distance further
increases.
Further to this example, by doubling the distance to 2600 m, the loss would be
203 dB, and
the same interference source would then be contribution less than 1% of the
FCC threshold
limit. In this example, the main beam of a satellite having a Full Beam-width
Half Power
point of 5 degrees is considered. Implementation of the present beacon
detection systems
and methods on existing conventional satellite systems link budgets of
approximately 200-
220 dB would thus enable measurement and control of all significant
interferers within the
main beam of the satellite. This particular example represents a worst case
scenario, in the
sense that an FSS with higher elevation angles would require a lower
protection budget,
and thus support a greater beacon transmission detection range.
[00289] At present, the United States contains a relatively large number of
registered FSS sites across the country (e.g., approximately 4700), the
positions of which
correlate fairly closely with the population density, and thus the relative
levels of mobile
use by such populations. Theoretically, a number of the registered FSS sites
may not be in
use, it is nevertheless believed that the number of sites that are actually in
use is quite high,
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and may even exceed the number of officially registered FSS sites when
unregistered FSS
sites are considered. However, unregistered FSS sites that consider future
mobile use for
this spectrum are more likely to seek registration. Accordingly, in the case
where different
APs are likely to share the 3.7-4.2 GHz spectrum, these APs are likely to
affect more than
one FSS site within range of the AP (e.g., registered and unregistered).
[00290] The detection range of an FSS site might be seen as limited, when
considering only that FSS site and its beacon detector individually, and also
compared with
present limits of 150 km and 40 km. However, if all of the beacon detectors of
the
infrastructure are considered together, the detection range may be
significantly increased.
Specifically, by implementing a beacon detector at each FSS site, and then
networking all
of the beacon detectors to the central server/SAS, the detection range is
effectively
extended considerably beyond the 2.7 km that might be expected according to
the
propagation model calculations described above. Other morphologies may support
significantly higher distances due to lower attenuation losses. According to
the present
embodiments, the detection range can be extended even further through the
calibration
techniques of the propagation model using the real-time measurements of the
MBP, as also
described above.
[00291] For example, when a beacon is transmitted (e.g., by a new AP
requesting to transmit) below the capability of the individual site to detect
the beacon, the
broadcast beacon still may be detected by other beacon detectors (i.e., at
other sites) during
the initial registration process of the AP/transmitter, and without causing
significant co-
channel interference. The present systems and methods thus advantageously
utilize beacon
detections from other sites (whether registered or unregistered) to
effectively extend the
range of beacon detection for the first FSS site of interest. The APs from
other sites would
not cause any significant interference to the local individual FSS.
Nevertheless, through
use of the larger network of beacon detectors and the MBP system, it is
possible to
accurately determine the other APs' contribution to blocking and total
aggregation effect,
with respect to the co-channel, first, and second interference limits at the
individual FSS.
Where the other APs are within the control of the central server, the central
server is further
enabled to more effectively manage the outside APs.
Additionally, the present
embodiments further enable the central server to effectively detect beacon
transmissions
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according to the radio access point information used in the propagation
measurements
described above.
[00292] Thus, as each beacon detector reports to the central
server(s)/SAS, the beacon transmissions across the entire country (or area of
beacon
infrastructure deployment) are detectable anywhere where people live, as
emphasized
below with respect to FIG. 15. That is, a beacon transmitted on the east coast
of the
country is detectable with respect to an FSS site on the west coast, through
the central
server and the reporting system of the infrastructure embodiments described
above.
[00293] FIG. 15 is a graphical illustration depicting a plot 1500 of an
addressable population 1502 (in percent) with respect to a radius 1504 (in km)
of an
exclusion zone (e.g., first area zone 1104, FIG. 11A). Plot 1500 is therefore
of particular
value for use in estimating overlap of coverage according to the embodiments
described
above. Coverage overlap is an important consideration in LTE systems. In an
exemplary
embodiment, plot 1500 illustrates a statistical analysis of the U.S.
population based on U.S.
census data sets (ESRI) showing the average effects of an exclusion zone
radius around
each of the 4700 FSS sites described herein. This analysis enables effective
removal from
radio coverage of portions of the population around the respective FSS sites.
For example,
with an exclusion zone radius of zero around each FSS site, approximately 99%
of the U.S.
population would be within the coverage area. In comparison, with an exclusion
zone
radius of 25 km, approximately 10% of the U.S. population would be within the
coverage
area. Accordingly, the positions of these FSS sites collectively provide radio
coverage for
nearly the entire U.S. population (e.g., also considering the unregistered FSS
sites to reach
the greater-than-4700 number).
[00294] In the example depicted in FIG. 15, a simplest path loss model is
able to assume that the received power (in dBm) may be calculated according
to:
ndB(d) = odB(do)- OBetaLogio(d/d0)-Fer (Eq. 1)
[00295] where d represents the distance in meters, and 1ld13 (do) represents
the received signal power at a known reference distance in the far field of
the respective
transmitting antenna, which may be 1 km for a macrocell, for example, 100 m
for typical
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outdoor microcells, and/or 1 m for a typical Pico-cell. In contrast, the value
for S2,18(do)
will be dependent on the frequency, antenna heights, gains, etc., as well as
other
environmental factors. Beta represents the path loss exponent parameter, and
will be more
dependent on the cell size and the local terrain. In some embodiments, the
path loss
exponent Beta may range from 3 to 4 for a typical urban macrocell environment,
and from 2
to 8 for a microcellular environment. In the exemplary embodiment, the loss
exponent Beth
is determined by system 1200 (e.g., central server 1202) for each individual
interferer, and
each such exponent value may be used to further build the detailed local
propagation
model. The term et represents a zero-mean Gaussian random variable (in dB),
and
represents the error between the actual and estimated loss.
[00296] Shadow and corner effects will cause variance in the measured
received signal power 0,113(d) (e.g., by beacon detector 1214, FIG. 12).
Accordingly, the
statistical variation of the measured QdB(d), caused by shadowing, may be
modeled as
being log-normal distributed according to the following equation:
pC2dB(x) ¨(1/q2nso)exp { -(x-U)/2 05Q2) (Eq. 2)
[00297] where 6E1 represents the shadow standard deviation. Thus, a more
accurate path loss determination will result in in smaller values being
obtained for ön In
the case of macrocells, values for 8E2 may range between 5 and 12 dB, with 8
dB
representing a more expected value. In this example, Sn may be observed to be
substantially independent of the path loss distance d.
[00298] As described further herein, the present beacon infrastructure and
beacon transmissions are of particular use in the dynamic and real time
determination of
the path loss model. For example, when a beacon is transmitted by a radio AP
and detected
by the beacon detector (e.g., at an FSS site) the transmitted beacon will
provide a path loss
value according to Eq. 1, above. From this detected value, the central server
may
determine the path distance d according to several conventional techniques,
including use
of the known geographical coordinates for both of the AP and the FSS site,
which may, for
example, be pre-loaded into the central server database. In some instances,
and particularly
at the initialization phase, an AP may not have any UEs associated there with,
and thus no
additional interference from the UEs will be calculated. Nevertheless, some
statistical
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variation in the measured received power will still occur, due to multipath
and shadowing
effects, but may be accounted for by the value for er.
[00299] In an exemplary embodiment, a determination scheme for a
propagation model calculates the additional interference for both the APs and
the UEs.
After the initial determination, subsequent measurements of beacon path loss
will
advantageously provide further information useful for calculating the value of
er. In this
example, er may be represented by a probability density function, which is a
zero-mean
Gaussian random variable. An average value for this probability density
function may then
be determined from repeated measurements, and will provide an accurate
estimate for
PL(do)-10BetaLogth(d/do). In some embodiments, the same measurements are
further useful
to determine the value for Beta according to curve fitting mechanisms and
other
mathematical techniques.
[00300] In most instances, the path loss exponent Beta will be strongly
dependent on the cell size and the local terrain. Accordingly, the present
techniques are
further advantageous in that they may be extended to other locations in a FSS
locality (i.e.,
the FSS cell site) to determine a representative value of Beta for that
locality.
[00301] The techniques herein are still further effective for modeling the
effect of UEs on the dynamic system model. For example, once the parameters of
Eq. 1
have been established, and the AP is authorized to transmit (according to one
or more of
the processes described above) the central server may be further configured to
assign an
EIRP power such that the authorized AP transmissions will be below an
interference
threshold, such as a predetermined threshold. In the exemplary embodiment,
central server
may determine the initial association of UEs without first performing such
calculations. In
this case, after the initial association, subsequent calculations may be
performed to
represent the interference effect from the UEs, and the transmitter EIRP may
be
dynamically modified to represent the AP EIRP, as well as the sum of UE
transmitter
powers associated with that AP. According to this embodiment, a more
accurate
interference calculation may be performed by the central server for extending
the spectrum
access sharing system.
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[00302] In this example, the central server is configured such that the
effective transmitter EIRP of the AP reflects, in real-time, the number and
type of UEs
associated with that AP. The type of UE may be significant, in that the type
may determine
the duty cycle of the transmission (e.g., LTE FDD vs. LIE TTD). The number and
type of
associated UEs may be communicated, for example, over a fixed line connection
(e.g., AP
data link 414, FIG. 4) from the AP to the central server or SAS. By using a
fixed line
connection in such manner, the system avoids having to transmit this
information with the
beacon each time there is a change to the number of associated UEs. In some
embodiments, the signaling load may also be reduced by providing to the
central server a
predetermined assumption for the number of UEs associated with the AP, and
this
presumed value may be used as a threshold for the relevant calculations for
the effect of
UEs on interference. In other embodiments, the value is based on historic
records (e.g.,
day use vs evening use). This threshold presumption further provides a level
of safety
margin for the calculations when the number of associated UEs is actually
fewer than the
presumed value. In this case, when a presumed threshold UE value is used, the
central
server need only be updated when the actual number of UEs exceeds this
threshold value,
whether communicated over the fixed connection or transmitted with the beacon.
According to this exemplary configuration, the interference effect of UE power
is a
function of the multiple access scheme of the particular UE. For example, in
the case of
LTE TDD, the duty cycle of the transmission will modify the effective
interference effect.
In the case of CBRS device, a maximum value EIRP may be 23 dBm.
[00303] In these examples, the effective transmitter EIRP essentially
resembles a single point source with respect to the interference calculations.
That is, a
single received power value may be used to represent the AP and its associated
UE
community. According to the present embodiments, this particular technique is
effective
due to the relatively small cellular area of the AP (i.e., radius of coverage)
in comparison
with the distance to the FSS site, which may, in this example have
substantially similar
dimensions. Accordingly, higher-power APs may be deployed according to the
present
techniques that distance is farther from the FSS site.
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[00304] An alternative, or additional, safety margin for locality may be
provided using the error term er featured in Eq. 1, above. In an embodiment,
the error er
influences the link budget by providing a safety margin for the initial beacon
transmission,
which prevents the particular beacon signal from being used to interfere with
the FSS sites
in the local area. In one example, the link budget is optimized to allow a
highest
reasonable value for the error term eõ which will thereby produce the highest
potential link
budget. This exemplary configuration further enables the central server (or
other detectors)
to identify each separate AP from the beacon detection system of the FSS site,
and
determine the interference effects of each particular AP.
[00305] In some embodiments, these techniques are further applied to the
effective E1RP of an AP such that the determined value for the EIRP is
sufficient to include
the UEs associated with that AP. Accordingly, a statistical distribution
associated with the
particular AP will model the effect of multi-path and shadowing for both the
AP and its
associated UEs. Because the AP cellular area, and thus its radius of coverage,
is
considered relatively small in comparison with the distance to the FSS site,
the interference
may be approximated to a point source. The individual power of the associated
UEs will
be, in this instance, significantly smaller than the power of the AP, and
therefore any
additional increase to the parameter 8E2 (e.g., from a building corner effect
(FIG. 12B)) may
be considered relatively insignificant. Accordingly, in some examples, a lower
bound of
propagation path loss, such as from conventional modeling techniques, may be
used for the
determination of initial beacon transmission power. This lower bound
represents the most
conservative static and value that will ensure no significant interference.
[00306] The value of error Cr further extends to determinations of ongoing
AP/associated UE use. For example, when a particular AP is authorized to
transmit at a
particular power on a particular channel, there will be an expected
statistical variation to
the measurable interference that the FSS site will experience. Using this
expected
statistical variation, the central server may be configured to use a higher
value for the error
er than would be required for the conservative conventional propagation model.
In one
example, the central server is configured to use the statistical averaging of
path loss value
for AP transmitter powers across the locality, such that somewhat higher
transmitter
powers may be authorized, but without increasing the risk of interference to
locality. By
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allowing higher transmitter powers within the locality, significant increases
to the coverage
and capacity of the system are advantageously realized.
[00307] In the examples described above, a 4 dB improvement to the
transmitter power (and thus the link budget as well) is realized in comparison
with
conventional techniques that are limited to using only the lower bound of
propagation loss
(e.g., based on known for macrocell parameters). This 4 dB improvement though,
only
reflects the initial gains from the improved calculation model. The present
systems and
methods achieve still further improvements to the link budget due to the real-
time MBP
configuration of the network, which may dynamically optimize the model such
that
improvements of up to 8 dB or greater are realized during operation.
[00308] The improved MBP propagation model of the present
embodiments therefore provides a number of significant advantages in
comparison with the
conventional modeling techniques. The present techniques are able to ensure
that an initial
beacon transmission will not cause interference to the FSS site. Indeed,
according to the
present techniques, the central server may be configured to utilize the
highest value of
beacon transmission power to actually enhance the link budget. These
techniques further
enable the more efficient use of the allocation of transmitter powers based on
derived
information of APs within a locality, which will realistically yield a 4-8 dB
improvement in
transmitter power. The dynamic propagation model of the present embodiments is
also
scalable, and may be extended to model the AP itself, and/or its associated
UEs, using the
effective EIRP of the AP.
[00309] The number of associated UEs for a given AP may thus be
presumed according to a predetermined threshold, and/or updated in real-time
over a fixed
communication link of the network to reduce signaling load. Moreover, the
present
systems and methods are capable of dynamically "learning" the average number
of UEs
associated with an individual AP, and such learned values may be retained
(e.g., by the
central server database), thereby further reducing the potential signal load.
These learned
values may, for example, further includes a statistical association of UEs
according to a
time of day, week, etc., and apply these learned values to the
calculations/models as well.
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[00310] In the example depicted with respect to FIG. 15, ZC sequences
are known to be utilized in LTE systems such as the 3GPP LTE air interface in
the Primary
Synchronization Signal (PSS), the random access preamble (PRACH), the uplink
control
channel (PUCCH), the uplink traffic channel (PUSCH), and the sounding
reference signals
(SRS). In such systems, orthogonal ZC sequences are assigned to each LTE
eNodeB, and
the transmissions of these sequences are multiplied by their respective codes.
Accordingly,
the eNodeB transmissions are uniquely identified, while the cross-correlation
of
simultaneous eNodeB transmissions and the inter-cell interference are reduced.
In an
exemplary embodiment, the present systems and methods implement ZC sequences
to
achieve further advantages according to the valuable properties thereof.
[00311] A ZC sequence is a complex-valued mathematical sequence
which, when applied to radio signals, gives rise to an electromagnetic signal
of constant
amplitude. Cyclically shifted versions of the ZC sequence, when imposed on the
signal,
result in zero correlation with one another at the receiver of the signal. A
generated ZC
sequence that has not been shifted is referred to as a "root sequence," and
such sequences
exhibit the useful property that cyclically shifted versions of themselves are
orthogonal to
one another, provided that each cyclic shift, when viewed within the time
domain of the
signal, is greater than the combined propagation delay and multi-path delay-
spread of that
signal between the transmitter and receiver.
[00312] It has recently been proposed that a 100 MHz portion of the 500
MHz of C-band spectrum be allocated for mobile use (e.g., LTE). This proposed
allocation
would leave the remaining 400 MHz available for implementation of the MBP
scheme for
spectrum sharing. As described above, some embodiments utilize a guard band
for
transmission of the beacon signal. Under these new proposals, the ZC sequence
beacons
may be alternatively or additionally utilized for the same purposes within
this new mobile
band, and without causing interference to other mobile users of that band.
Under this new
proposal, users sharing the 400 MHz spectrum portion could be provided
additional access
to this new 100 MHz portion of mobile spectrum for beacon transmissions. Users
that do
not access this 100 MHz portion would still be able implement the adjacent
guard band
solution described above. Alternative proposals allocate 200 MHz of the
available
spectrum, and/or upper or lower portions thereof. The person of ordinary skill
in the art
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will understand that the principles of the present embodiments are not limited
to 100 MHz
or 200 MHz, or upper or lower edges of a given spectrum, such as the C-band.
[00313] While the propagation characteristics of a different band (e.g.,
new 100-300 MHz allocation portion) for beacon transmission may be different
than that of
an adjacent guard band in close proximity to the channel in use, assuming
implementation
in the 3.7-3.8 GHz spectrum, MBP measurements in this new band are expected to
indicate
a more conservative protection scheme, since the measurements thereof would
yield lower
propagation losses than experienced at higher frequencies. Alternatively, the
central server
may further utilize a calibration parameter to correct for this propagation
loss difference.
The systems and methods herein are also advantageously capable of further
adaptation such
that the beacons utilize other radio bands, such as the CBRS band, as an
alternative
solution where warranted.
[00314] Implementation of this new proposed 100 MHz portion (or
similar) will influence the choice between an adjacent guard band and this
different band
according to such considerations as (i) beacon range (e.g., due to differences
in beacon
transmitter power), (ii) similar propagation characteristics, and (iii) the
ability to accurately
predict the actual channel characteristics of the signal channel as well as
access rights to
this new mobile band for transmission of the beacon. It is expected that this
new 100 MHz
band portion, if implemented as proposed, will be used for 5G Mobile, in which
case the
existing infrastructure for LTE ZC functionality may be advantageously
utilized to transmit
the beacon functionality described herein.
[00315] As described above, WSJT techniques achieve notably superior
SNR values below the receiver threshold. However, these techniques require
very accurate
alignment of the receiver local oscillator with the transmitter for successful
and fast
detection. As also described above, the phase drift (phase noise) of the LNB
down
conversation may span several kHz, and therefore typically require expensive
GPS
discipline Rubidium sources. Conventional ZC implementation techniques may
require,
for example, a 1 W/3.25 MHz transmitter power, a high gain multiple-input and
multiple-
output (MIIVIO) antenna (e.g., steerable such that, as gain increases, so does
the antenna
directivity, thereby reducing the angular field of view) as a separate beacon
detector or
satellite gain, as well as a low-noise receiver, to achieve 6 dB higher than
WSJT
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performance, as illustrated in Table 3, below, due to the receiver antenna
gain. As
described above, 198 dB may be realized in the case of an isotopic receiver.
Alternatively,
the implementation of WSJT with MIMO or satellite gain would likely yield
higher than
ZC values, According to the present techniques, however, such obstacles are
overcome,
and particularly with respect to the LNB down conversation.
[00316] In an exemplary embodiment, the present techniques convert
(e.g., at the central server) a linear convolution to a circular convolution
by repeating one
ZC sequence shoulder-by-shoulder. Through this innovative technique, applied
to the
beacon infrastructure described above, the individual computation speed is
reduced from
N*N, to N*logN, which will thereby avoid an N-squared computation problem seen
using
conventional modeling techniques.
[00317] This exemplary technique therefore utilizes ZC sequences to
resolve the budget for the beacon-based systems and methods described above.
According
to an exemplary calculation, the maximum path loss (MPL) may be represented by
the
equation:
MPL = Tx ¨ Rx + Gain(Rx) + SNR (Eq. 1)
[00318] Where Tx represents the transmitter power of the beacon (i.e.,
ERIP) per MHz, Rx represents the sensitivity (noise power per MHz = Noise
Figure*k*T*B) of the receiver, where T=300K and k=1.38 10exp (-23), Gain(Rx)
represents the gain of the beacon detector, and SNR represents the signal-to-
noise ratio
value below the receiver sensitivity (e.g., coding gains, etc.). Accordingly,
the budget may
be thus calculated in consideration of the values depicted in Table 3, below.
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TABLE 3
ZC Budget value units
(3.25 Mbits baud rate)
Transmitter Power: 25 dBm/MHz
1 W per 3.25 MI-lz
Bandwidth 3.25 MHz
Rx Noise Power -112 dB m/MHz
(Noise Fig. = 1.5 dB)
Rx S/N -30 dB
Rx Antenna/Satellite Gain 37 dB
Max Path Loss 204 dB
[00319] It can be noted, from Table 3, the significant role played by the
receiver gain. In at least one embodiment, by directly using the actual
satellite dish gain
with in-band detection having a post-LNB of approximately 37 dB (e.g., for a
2m dish), a
204 dB link budget can be achieved. In an exemplary embodiment, the
transmitter power
Tx of the beacon is further increased using the guard band. In some
embodiments, the
SNR and/or the receiver gain are also further increased. These additional
increases may be
of particular advantageous value in the case where both external and in-band
satellite
beacon detection are performed together.
[00320] Table 4, below, illustrates the change in beacon range, below
clutter, for use in (i) residential, (ii) residential/commercial mixed, and
(iii) high density
commercial implementations. In the exemplary MPL budgets depicted in Table 4,
ZC
sequences are implemented at 3.25 MHz, with receiver power established at
NF=1.5 dB,
and T=300K. In this example, the beacon Tx 25 dBmfMHz (i.e., at 3.25 MHz), and
the AP
transmitter power is 20dBm/MHz (at 10 MHz) for a class A CBRD.
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TABLE 4
Transmitter Maximum Path Beacon Range Beacon Range Beacon Range
Power Loss for ZC:
(dBm)
(residential, (residential/commercial (high density
Single
commercial
below clutter) or mix below clutter)
Interferer below
clutter)
[D>200: [D>200: [D>200:
-53 .9+75LogD] -31.2+40LogD] -31.2+40LogD]
25 192 dB 1.9 km 10.5 km 6.8 km
35 202 dB 2.6 km 18,6 km 12.1 km
42 209 dB 3.2 km 27.9 km 18.1 km
[00321] These innovative techniques for extending the ability to detect the
beacons well beyond the beacon transmission range provides further advantages
to satellite
protection schemes. For example, conventional satellite protection regulations
require
consideration of distances of up to 40km for blocking, and up to 150km for the
co-channel
implementations described above, both of which are significantly greater than
the
transmission range of the beacons. Nevertheless, considering a link budget
greater than
approximately 210.5 dB (i.e., 30dB above 180.5 dB), for the worst case
scenario of the
lowest satellite elevation of 5 degrees, at an azimuth of 0 degrees, the
integral power for
small cell deployments, below clutter and beyond the beacon range boundary,
will
generally be insignificant, as illustrated below with respect to Table 5. In
the case where
the small cell integral power is considered to be greater than this
insignificant amount, the
integral power may be addressed, if necessary, by slight increases to the
protection limit.
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TABLE 5
Free space Residential below Residential/ High
density
clutter commercial mix commercial
below clutter below clutter
a 44.3737141 -53.9 31.2 38.7
20 75 40 40
Small cell 37 20 20 20
power/dBm
Cell size/ 1000000 1000 500 100
mA2
Link budget 150000 1200 1200 1200
boundary/m
Integral -111.152828 -156.3941159 -127.3545513 -
127.8648512
power
outside
boundary/
dBm
[00322] FIGS. 16A-16B illustrate data tables 1600, 1602 for satellite
protection MPL with respect to a single AP, and 800 APs, respectively, within
the satellite
beam width. In the exemplary embodiments illustrated in data tables 1600 and
1602, the
MPL is 192 dB, which is capable of managing 800 CBSDs, which is indicated by
the
values contained within data table 1402 specifically, representing a worst-
case scenario.
Small cell considerations are described above. Macrocell interference
considerations may
be calculated with respect to Table 6, below.
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TABLE 6
Elevation Gain Below Clutter Above Clutter Above Clutter
(degrees) (dB) Residential (km) Residential (km) Residential/
1-53 .9-F751ogD1 [-100+75logD] Commercial Mix (km)
1-13.3+501ogD]
14.53 2.47 10.18 18.95
7.00 1.96 8.08 13.40
2.60 1.71 7.06 10.94
-0.53 1.56 6.41 9.48
-2.95 1.45 5.95 8.48
-4.93 1.36 5.60 7.74
-6.60 1.29 5.32 7.16
-8.05 1.24 5.09 6.70
48 -10.03 1.16 4.79 6.12
[00323] It is noted that, with respect to the values illustrated in Table 6,
the calculations do not assume the use of MIMO antennas or real gain of the
satellite dish
(37 dB in the case of a 2m dish). The satellite gain is calculated using the
standard ITU
equation for interference calculations. In such cases of MIMO implementation,
the
interference considerations are presumed to be worse. For the macrocell
calculations
illustrated in Table 6, the exemplary transmitter power (EIRP) is 37dBm/MHz
(50W in a
10 MHz band), and the interference is assumed to be equal to 1% (-20 dB) of
the satellite
threshold of -129dBm/MHz. This assumption therefore effectively takes into
account more
than one single interferer with a safety margin. The calculations illustrated
in Table 6
further take into account the satellite elevation, satellite dish azimuth of 0
degrees and thus
the gain, for this form of co-channel interference. These calculations
additionally
implement the exemplary measurement model described above, which is suitable
for
residential/commercial use. A rural-based model, on the other hand, would
predict larger
propagation distances, and the macrocells may be constructed to be above
clutter for
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greater coverage. Nevertheless, the first column of Table 6 illustrates a
residential case
below clutter.
[00324] According to the exemplary calculations included in Table 6, that
can be seen that a safe macrocell distance, according to these parameters, is
found between
km and 19 km for low elevations (e.g., 5 degrees), but may be as low as
between 5 km
and 7 km at 35 degrees. Given the density of FSS sites in residential and
residential/commercial type areas across the country, where the "blocking
effect" is
greatest, the use of 3.7 GHz for macro-cells may not be practical. That is,
when the
particular transmitter is that far from a single FSS site of concern, it is
highly likely that the
transmitter is closer in distance to a different FSS site. In this example, a
relatively low
transmitter power (in compaiison with normal power) is assumed for the macro-
cell, In
this case, range extensions using MIMO antennas may be less practical, and
instead
contribute to interference and possibly increase the safe operating distances.
[00325] As illustrated in Table 6, the calculated results in the case of
below clutter indicate that the safety distance is approximately 1.3 km for an
in-band
transmitter at 35 degrees. It should be noted, that in this example, a higher
transmitter
power (Cat B Rural) is used for the calculation than would be the case for a
typical indoor
CBRS AP. The present techniques are not bound by such limitations though,
because the
3.7 GHz spectrum is not generally considered to be particularly suitable for
macro cellular
coverage due to its poor propagation, and particularly with respect to handset
devices that
are limited in transmitter power for the return path, and therefore cannot
utilize MIMO of
significant proportions. Nevertheless, the present embodiments consider the
3.7 GHz
spectrum because it may still affect the FSS site(s) of concern. Additionally,
there exist
other low frequency bands that would not cause interference to the FSS site,
and which
may be re-purposed for similar use.
[00326] Accordingly, these macrocell considerations further emphasize
how the 3.7 GHz spectrum is of particular value for use with small cells, as
described
above, similar to the power bands utilized for CBRS, namely, the 1W, 4W and
50W power
bands. The present embodiments still further demonstrate the advantages
obtained through
utilizing beacons in the macrocell, wherever such implementation is possible,
and
particularly in instances outside of the United States regulatory structure.
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[00327] In another embodiment, number range reuse techniques provide
an alternative process to increase the maximum path loss for beacon detection.
In this
example, the transmitted beacon includes information for successful operation,
including
without limitation one or more of: (i) the unique ID of the AP; (ii) the
transmitter power;
(iii) the signal channel(s) desired on which to transmit; (iv) the AP
location; etc. In some
embodiments, the present systems and methods limit the information included in
the
beacon so as to minimize the bit rate and/or duration of the beacon
transmission that might
potentially detract from the MPL budget or overall ability of the system to
detect and
rapidly protect from interference. In at least one embodiment, only the unique
ID of the
radio AP is transmitted over the air, and other information is transmitted to
the central
server/SAS over a fixed network along with the AP unique la
[00328] In this embodiment, supporting a number range of up to 1 billion
(e.g., for potentially all possible future IDs) would require a binary work
length of 30 bits.
Reducing this binary work length to 16 bits would only allow a number range of
approximately 65 thousand, which would not be sufficient for this foreseeable
future use.
Such reduction though, would nevertheless increase the MPL budget by as much
as 3 dB,
while also reducing the speed of identification by nearly a factor of two. The
present
number reuse techniques realize the advantages obtained by reducing the binary
work
length, but without the corresponding conventional disadvantages of the
reduced number
range. These advantages are achieved by allocation to each FSS site a cell
around the site
in which each AP has a unique ID, but these unique IDs may be simultaneously
used
outside of the cell.
[00329] FIG. 17 illustrates a patterned grid region 1700 including a
plurality of contiguous grid blocks 1702. In the exemplary embodiment,
contiguous grid
blocks 1702 are illustrated as being substantially hexagonal for ease of
explanation. In this
example, a hexagonal shape approximates a round coverage area having a
somewhat
uniform radius from center, and which does not include gaps between respective
coverage
areas represented by grid blocks 1702. Additionally, the hexagonal boundary
shape
simplifies the discussion to ignore overlap of adjacent grid blocks 1702 (see
e.g., FIG. 13,
above).
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[00330] According to the exemplary embodiment, the present systems and
methods may utilize an 18-bit word, which would thus allow the reuse of 4
patterns, and
thereby accommodate approximately 65k APs per cell. In other embodiments,
reuse of a
greater number of patterns may be desired. Such higher reuse examples are
somewhat
similar in concept to Frequency Division Duplex (FDD) techniques used in
cellular
systems, where blocks of frequencies are used per cell with a reuse repeat
pattern. In at
least one embodiment, APs having the same ID may be differentiated from one
another by
use of triangulation by a network of beacon detectors.
[00331] According to the embodiment illustrated in FIG. 17, each of the
individual grid blocks 1702 in patterned grid region 1700 is assigned a
different one of six
individual use patterns (e.g., designated as letters A-G), and thus indicates
a cellular reuse
factor of 7. Each individual grid block 1702 therefore represents a different
block of 65k
numbers per lettered pattern, e.g., A65k, B65k, C65k, D65k, E65k, F65k, G65k.
Accordingly, similar to cellular network techniques, no two blocks of 65K APs
having the
same pattern (i.e., one of A-G) are immediately adjacent one another.
[00332] In an exemplary operation of patterned grid region 1700, a
triangulation scheme according to the present embodiments enables spatial
reuse of a first
grid block 1704 having pattern A. More particularly, the triangulation scheme
applied to
grid region 1700 effectively separates the number range used in pattern A from
being also
used in immediately adjacent blocks 1706. As illustrated in FIG. 17, in each
direction 1708
from first grid block 1704, at least two grid blocks 1702 of different
patterns (e.g., B-G) are
interposed between first grid block 1704 and each instance of a second grid
block 1710 that
uses the same pattern A.
[00333] In an embodiment, time division multiplexing techniques are
implemented, in an alternative or supplemental manner, to further separate and
extend the
reuse of number patterns A-G. For example, the system of patterned grid region
1700 may
be configured (e.g., at the central server) such that transmission in first
grid block 1704 is
controlled such that the APs of first grid block 1704 transmit on even number
days, while
the APs of an instance of adjacent block 1706 transmits on odd numbered days
using the
same number range of the pattern (e.g., pattern A) of first grid block 1704.
This time
division technique is scalable, and therefore may be further implemented to
alternate
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transmission at the odd/even minute level (or less) using the GPS technology
and
information within each block 1702.
[00334] Referring back to FIG. 5, in another embodiment, beacon
measurements may be obtained utilizing the LNB (e.g., LNB 530), the dish,
and/or the feed
horn of the earth station (e.g., earth station 504) of a particular FSS site
(e.g., FSS site 502).
A beacon receiver (e.g., beacon detector 528) communicates over an operable
data link
(e.g., reporting links 540, 542, 544, 546) to the central server (e.g.,
central server/SAS
510). In this example, the hardware of the particular dish/earth station may
serve as an
alternative to an outdoor beacon receiver and antenna, or multiple receivers
and antennas
per dish, by tapping into each FSS antenna signal distribution chain
downstream of the
LNB. The beacon may then be received at the down converted (IF) frequency of
the in-
band beacon signal, and the central server may then avoid having to adjust the
RSSI of the
beacon with respect to the FSS dish antenna gain, due to the beacon signal
having been
received using the FSS dish.
[00335] Alternatively, the present systems and methods may be instead (or
additionally) configured to utilize MIMO antennas to detect beacon
transmissions. More
particularly, instead of utilizing the beacon detection obtained after the LNB
down
conversion, an infrastructure according to this example may be configured to
deploy an
external antenna covering the 3.7-4.2 GHz band, and which can be orientated in
the same
direction of the satellite dish, or may be configured made such that it may
sweep a 360
degree rotation with a narrow beam and corresponding high gain. In this
alternative
embodiment, MIMO technology achieves at least 37 dBi of gain over angular view
greater
than the satellite beam width. A further advantage to this alternative
technique is that a
single external antenna may be deployed to cover the entire FSS site, which
may contain
many individual satellite dishes. In this example, only the single external
antenna need be
in operable communication with the central server. In at least one embodiment,
a parabolic
antenna is implemented, which realizes a 37 ciBi gain, covering the 3.4-3.7
GHz band, with
a beam width of 8.5 degrees that effectively complements the beam width of
satellites used
in the C-band.
[00336] In some embodiments, the link budget is still further extended
through an innovative implementation of MIMO technology. For example, since
the
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effective interference contribution outside of the beam width of the satellite
is -10 dBi,
which is approximately 47 dBi (37dBi + 10 dBi) less than that within the
satellite beam, the
most significant interference considerations are taken in the direction of the
satellite dish,
that is, within the satellite beam. However, since the antenna may be
configured (whether
electrically or mechanically) to sweep a 360 degree field of view, such use of
an external
antenna will require calibration with the satellites being protected, in order
to accurately
measure the relevant interference. In this embodiment, therefore,
implementation of the
external antenna provides at least a 10 dB improvement in maximum path
loss/range.
[00337] In one embodiment, the present beacon detection infrastructure
further utilizes the measurement-based propagation models, described above, to
extend the
effective range of beacon detection. As described above, the measurement-based
propagation techniques enable the central server to regularly and/or
constantly update the
propagation model(s) of the network, using information obtained from the
multiple APs
and beacon detectors that are integrated within the overall spectrum access
sharing system.
According to this MBP scheme, more accurate calculations of link budgets are
obtained in
the initial set up of channel allocations, and subsequent beacon transmissions
serve to
verify successful operation. Through these MBP propagation techniques, central
server is
advantageously configured to calculate not only the co-channel emissions, but
also the first
and second adjacent channel emissions to ensure regulatory compliance of the
network.
This measurement scheme is also further scalable to address the aggregate
interference
across the 500 MHz band, for example, by calculating the relevant LNB blocking
considerations. In one embodiment, such considerations may be limited at -60
dBm, or
measured directly by the beacon detector as part of its functionality.
[00338] FIG. 18 is a graphical illustration 1800 depicting comparative
data plots 1802 of dual-slope propagation models (i) at clutter, (ii) below
clutter, and (iii)
above clutter, and for each morphology of (a) high density commercial, (b)
residential, and
(c) residential/commercial mixed classifications. In the example illustrated
in FIG. 18, the
path loss (vertical axis, in dB) is plotted against distance (horizontal axis,
in meters) for
each model, and all such models are charted against a free space path loss
plot 1804. In the
exemplary embodiment, the resulting data plots 1802 represent empirical or
tuned 3.5 GHz
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dual-slope propagation models, as well as the dual-slope log-distance path
loss models for
all morphology/clutter classifications and free space loss.
[00339] As shown in illustration 1800, the "below clutter" data plots 1802
generally indicate the greatest path loss, whereas the "above clutter" data
plots 1802
generally indicate the least amount of and path loss. Additionally, the high
density
commercial morphologies similarly indicate greater amounts of path loss,
whereas the
residential morphologies indicate less path loss. Data plots 1802 are
illustrated in greater
detail below with respect to Table 7, which further provides breakpoint and
slope values
for each of the propagation models depicted as data plots 1802, and compares
these values
against relevant values of the single slope model.
TABLE 7
RESIDENTIAL RESIDENTIAL/ HIGH DENSITY
COMMERCIAL MIX COMMERCIAL
Below At Above Below At Above Below At Above
Clutter Clutter Clutter Clutter Clutter Clutter Clutter Clutter Clutter
(m) (m) (m) (m) (m) (m) OTO (m)
(m)
Dual Break- D<200 D<250 D<550 D<300 D<350 D<250 D<100 D<200 D<400
Slope point
Model 1st
slope
Break- D<200 D<250 D<550 D<300 D<350 D<250 D<100 D<200 D<400
point
2nd
slope
Single -10+ 21.3+ 30+ 35.2+ 20.5+ 9+ 39.2+
9.2+ 42.4+
Slope 57logD 41.6logD 32logD 38.9logD 43.3logD 42.5logD 39.1logD
47.7logD 29.5logD
Model
EXTENSIONS OF USER EQUIPMENT MANAGEMENT
[00340] As described above, the beacon-based infrastructure and
associated techniques are applicable to both UEs and APs, and that the
potential
interference effect of the UEs on the FSS site may be models using effective
EIRP
techniques. The examples described above are provided, without limitation, for
APs at a
"reasonable" distance from the FSS site, and in the case where the radius of
the AP
coverage is relatively small in comparison with the distance of the AP from
the FSS site
(e.g., approximately 500 m). The adoption of beacon transmitters within
individual UEs
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though, may be impractical according to present-day communication network
technologies,
given the significantly large number of UEs (and APs) presently in operation,
and the
reduced link budget of the UEs in comparison with that of the APs.
Nevertheless, the rapid
advances in technology and communication network transmission may make
possible, or
even necessitate, beacon transmissions from every LIE in the near future.
[00341] Beacon transmissions at the UE level, however, are of immediate
value in the case of APs relatively close to the FSS site (e.g., less than 500
m), where the
effects of the LIE transmitter power may vary greatly according to changing
locations of the
UE, such as when the UE is a mobile device. Such variation makes the UE more
difficult
to model, but much of this difficulty is resolved by real-time beacon
transmissions from the
UE. In one embodiment, the UE beacon transmissions may be triggered by a
client on the
UE device, which is instructed to operate according to management from the
central server
when the UE device comes within close proximity to the FSS site (and/or during
an initial
calibration phase). In this example, only this small subset of UEs, close to
the FSS site, are
affected in this manner.
[00342] During an initial calibration phase, the UE beacons associated
with a particular AP may be measured at different locations around the AP, and
such
measurements, together with measurement of the associated AP beacon, are
useful to
determine the effective AP transmitter power, as well as its statistical
distribution, which
will accurately estimate the interference effect of the AP/UEs combination as
a single point
source, and as function of the number of UEs. The dynamic capabilities of the
present
system further enable the development of a more detailed AP/UEs model over
time, during
the real-time operation of the system. The statistical model that is derived
therefrom is
particularly useful to determine the safe transmitter power of APs that are in
close
proximity to the FSS site, and to enable the central server to instruct one or
more UEs to
reduce their individual transmitter power when needed, or for the AP to reduce
its power
thereby reducing the coverage area and influence over the number of associated
UEs.
[00343] Such instructions from the central server, namely, for the
APs/UEs to reduce their allowable transmitter power, that further utilize
calculations that
consider the shadowing or cornering effects of buildings (e.g., FIG. 12B) as
mobile UEs
move in and out of direct lines of sight from the FSS site. By reducing the
allowed
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transmitter power of the AP itself, the central server is enabled to directly
reduce the AP
interference, as well as the geographic size of the AP coverage area.
Reduction in the size
of the AP coverage area will thereby also reduce the number of UEs that will
be likely to
be supported by the AP. In some instances, such AP power reductions by the
central server
are a useful tool to reduce or eliminate the shadow effects of buildings on
the cell edges,
where the relevant UEs may instead be supported by a CBRS or macrocell.
According to
this advantageous configuration, the overall effect on the system, from APs
having
associated LTEs, is significantly more deterministic.
[00344] The interference effect from the UEs themselves is considered
with respect to the exemplary values illustrated in Table 7, above, such that
a dynamic
propagation model may be derived therefrom. For this exemplary propagation
model, the
respective transmitter powers associated with the different devices is
obtained using the
values provided in Table 2, also above. The relevant propagation model may be
further
constructed to implement the following parameters included in Table 8, below.
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TABLE 8
PARAMETER VALUE REFERENCE
In-band interference
-128.35 FCC 96.17(a)(2)&(b)(1)
requirement (dBm/M11z)
Reference antenna (dBi) 2510g1032(theta)
FCC 25,209(a)(1)&(4)
CBRS BW (MHz) 20 NA
Aggregated blocking
-60 FCC 96.17(a)(3)&(b)(2)
requirement (dBm)
1st adj
40 ITU-R M.2109 7.2
Spectrum channel (dB) ..........................................
mask 2nd adj 52 http://wwwjatitorgivo1umesNo165No3/
channel (dB) 21Vo165No3.pdf
UE
Max Tx 13 FCC 96.4I
(dBm/MHz) ............................
power
37 FCC 96.41
Passband
insertion loss 0.5 FCC 96.17(a)(2)&(b)(1)
(dB)
1st adj
Reference
filter suppression 12.5 FCC 96.17(a)(3)&(b)(2)
(dB)*
2nd adj
suppression 33 FCC 96.17(a)(3)&(b)(2)
(dB)*
[00345] =Using the parameters provided in Table 8, propagation losses
between the UE, and the FSS site may be calculated such that an interference
level of no
greater than -129 dBm/MI-lz, for example, is achieved, as indicated below with
respect to
the values provided in in Table 9. In the case where a pass band response is
considered, the
optimum interference level may be, for example, no greater than -128.35
dBm/MHz.
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TABLE 9
,
Link budget (dB)
Antenna
Elevation 1st adj 2nd adj 1st adj 2nd adj
gain 1n-band
degrees (,,dBi) blocking blocking emission emission
....
UE UE UE UE UE
14.53 155.38 89.33 67.73 115.38 103.38
7.00 147.85 81.80 60.20 107.85 95.85
1,5 2.60 143,45 77.40 55.80 103.45
91.45
-0.53 140.32 74.27 52.67 100.32 88.32
-2.95 137.90 71.85 50.25 97.90 85.90
-4.93 135.92 69.87 48.27 95.92 83.92
-6.60 134.25 68.20 46.60 94.25 82.25
-8.05 132.80 66.75 45.15 92.80 80.80
48 -10.03 130.82 64.77 43.17 90.82
78.82
[00346] From the values obtained above, the central server may be further
configured to calculate corresponding protection distances according to the
parameters
depicted in Table 10, below (i.e., illustrating the residential example, below
clutter).
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TABLE 10
= Protection distance for UE below clutter (m)
Antenna
Elevation
gain. In-band 1st adj 2nd adj
degrees
(dBI)
1:1E UE UE
14.53 617.08 168.32 91.09
7.00 489.78 114.52 61.98
2.60 427,86 9:1.42 49,48
-0.53 388.74 77.92 42.17
-2.95 360.87 68.84 37.25
-4.93 339.59 62.20 33.66
-6.60 322.58 57.10 30.90
-8.05 308.54 53.02 28.69
48 -10.03 290.35 47.91 25 93
[00347] According to the values depicted above, for the case of residential
below clutter, several determinations may be made: (i) at low elevation (e.g.,
5 degrees),
the LIE exclusion zone is 617 m for co-channel use, however, the central
server of the
present system may utilize an optimization algorithm with respect to the use
of the 2nd
Adjacent channel, and then the 1st Adjacent channel, in zones around the FSS
site,
effectively reducing the exclusion zone radius to approximately 91-168 m,
respectively;
and (ii) at 35 degrees, the in-band UE protection distance is approximately
322 m, and the
1st Adjacent band protection distance is approximately 57 m.
[00348] In this example, the exemplary values provided in Table 10 are
applicable within the range of the main beam, which has a half power beam
width (HPBW)
of approximately 5 degrees for a 2 m satellite dish. Outside of the main beam
(assuming
the "teardrop" shape of the respective zones described above), the gain
rapidly approaches
a value of -10 dBi, thus accounting for the reduction of the in-band
protection distance
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from approximately 617 m to 290 m, and the reduction in the 2nd Adjacent
protection
distance from approximately 91 m to 26 m. Further to this example, it is
assumed that UEs
are likely to be inside buildings (which may typically require 17 dB of
additional link
budget). However, for ease of explanation, the above Table values are provided
for a case
assuming that the UEs are located outside of buildings.
[00349] The analysis of the data provided in Table 10 may be similarly
applied to data for the at-clutter model, as provided below in Table 11, and
to data for the
residential above-clutter model, as provided further below in Table 12.
TABLE 11
Antenna for UE distance at clutter (m)
Elevation
'
gain in-band lst adj
degrees (m
T TE
14.53 1554.23 246.17
7.00 1099,01 1.54.11
2.60 897.33 117,18
-0.53 777,11 96.48
-2.95 695.07 82.98
-4.93 634.51 73.36
-6.60 587,44 66.10
-8.05 549.50 60.40
48 -1Ø03 501.63 53.40 ,
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TABLE 12
for UE distance above clutter (m)
Antenna
Elevation
gain. In-band 1St adj 2n.d adj
degrees
(dBI)
IJE .1:3E UE
14.53 2541.03 744.18 514.85
7.00 2016.82 780.73 196.11
2.60 1761,85 470.31 118.14
-0.53 1600.75 328.26 82.45
-2.95 1486.00 248.36 62.38
-4.93 634.51 197.74 49.67
-6.60 1328.34 163.09 40.97
-8.05 1270.52 138.01 34.67
48 -10.03 1195,60 109.89 27.60
[00350] According to the values depicted above, determinations may also
be made for the case of residential above clutter: (i) at low elevation (e.g.,
5 degrees), the
UE exclusion zone is 2541 m for co-channel use, however, the optimization
algorithm
applied to the 2nd Adjacent channel, and then to the 1st Adjacent channel,
effectively
reduces the exclusion zone radius to approximately 515-744 m, respectively;
and (ii) at 35
degrees, the in-band UE protection distance is approximately 1328 m, and the
1st Adjacent
band protection distance is approximately 163 m and the 2nd Adjacent band
protection at
41m.
[00351] In this example, "clutter" is determined to be approximately 20 m,
which reasonably represents a three-story high building having UEs located on
the third
floor. In practice, the UEs are likely to be inside the building, and also
located on other
floors. Similar to the below clutter model considerations, above, outside of
the main beam,
the gain rapidly approaches -10 dBi rapidly, thus accounting for the reduction
of the in-
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band protection distance to approximately 1195 m, and the 1st Adjacent band
protection
distance two approximately 110 m. Furthermore, at low elevations, a clear line
of sight to
the main beam is more necessary, since there is less likely to be building
interference above
the building clutter, Accordingly, in practical applications, and FSS site
disposed above
clutter would realistically experience less interference than the values
provided in the
Tables above. The shadow/corner effects described herein are more likely to
occur below
clutter (e.g., at or near ground level).
[00352] According to these models, it can be seen that UE migration may
be analyzed according to techniques similar to the other morphologies
described herein.
For example, with respect to the values for the 1st Adjacent channel, the
above clutter
protection distance of 744 in is reduced to approximately 168 in at a 5 degree
elevation for
below-clutter, and further to 57 m at a 35 degree elevation. Outside of the
main beam, a
similar protection distance reduction would be realized, i.e., from 109 m to
48 m. These
modeling values therefore demonstrate the proximity effect of UEs considered
to be
"close" to an FSS site, and therefore also the considerable value in
implementing a UE-
specific beacon to enable measurement of the actual UE interference, as well
as the
variance of the UE transmission caused by shadowing/cornering effects.
[00353] The embodiments herein this also demonstrate the particular
value of summing an aggregate of UEs as a single reference point to model the
effective
EIRP. In the exemplary embodiment, the UE beacon itself may be transmitted at -
7 dB
with respect to a Category A AP, -24 dB with respect to a Category B rural AP,
or -17 dB
with respect to a Category B non-rural AP. The implementation of the present
MBP
techniques at the AP level further advantageously enables the AP to determine
when UE
beacons are activated, thereby further significantly reducing the
signal/computational load
on the central server/SAS.
BEACON RECEIVER IMPLEMENTATIONS AT EARTH STATION SITES
[00354] The beacon transmission/receiver infrastructure described above
detects beacon transmissions throughout the system to determine, in real-time,
the potential
for interference at FSS earth station sites. The following description
provides further detail
regarding the exemplary implementation, distribution, and operation of the
exemplary
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beacon receivers/at and among the FSS earth station sites. As described
herein, the present
systems and methods achieve significantly improved measurements with respect
to
conventional techniques, and also more accurate estimates of interference
levels in
comparison with single detector operations.
[00355] As described above, mobile communication systems may coexist
with satellite communication systems in the same CBRS band, but there are
fewer than 20
such FSS sites across the United States, and having respective frequencies of
operation
restricted to the top end of the CBRS. Nevertheless, these FSS sites at
present have large
associated protection areas effectively segregating wireless and satellite
users. System
operators and the FCC are presently considering to additional spectrum within
the 3.7-4.2
GHz, 5.925-6.425 GHz, and 6.425-7,125 GHz bands for flexible use, such as for
mobile
communication (5G in particular) in the United States. For ease of
explanation, the United
States is discussed herein by way of example, but is not intended to be
limiting. The
principles of the embodiments herein are applicable to other countries and
their respective
communication systems and networks.
[00356] With respect to the 3.7-4.2 GHz band, for example, 12 channels
are provided for the downlink satellite communications, with 40 MHz channels
spanning
each polarization. At present, thousands of earth stations operate in this
band across the
United States, and require protection from radio interference from other
wireless services.
In the United States, the FCC regulates the interference levels from such
services that share
the same band.
[00357] In operation, the interference level from other wireless services
may be measured (e.g., according to the techniques herein) or calculated
(e.g., according to
conventional techniques or conservative propagation models) as described
above, at a
reference point disposed at the output of a reference RF filter (RRF), such as
between the
feed horn and the LNB (described further below with respect to FIGS. 20 and
21). In
conventional systems, each implementation of proposed sharing is performed in
consultation with other FSS users, and using conservative radio planning tools
in models.
Such implementations typically require months to complete the necessary
consultation and
modeling of the respective proposal.
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[00358] The innovative systems and methods described above though,
provide new and improved techniques for coexistence of terrestrial wireless
systems (e.g.,
including mobile communication systems) with satellite systems. The present
techniques
are drawn to a new operation model that expands upon the promotion of CBRS at
the 3.5
GHz range, as described above. In the exemplary embodiment, a coexistence
mechanism
is advantageously utilizes priority tiers, protection zones, and coordination
through a
central server/SAS to plan use based initially on conservative propagations
models, but
which is also dynamically adjustable in real-time to the actual operational
conditions of the
system. In some embodiments, particular critical communication systems or
subsystems
(e.g., security or safety systems) may be assigned to have the highest
priority use of the
larger system, or portions thereof.
[00359] As described in detail above, the beacon infrastructure of the
present systems and methods is unique to this field of technology, and
advantageously
provides a system for sharing the given satellite band spectrum with other
wireless users,
while also protecting FSS installations. In the exemplary embodiment, low
power level
radio beacons are implemented at each AP, and may be configured during
registration to
estimate in real-time the potential interference levels to FSS sites, and in
coordination by
the central server. In the exemplary embodiment, each FSS site is provided
with its own
beacon detection system to measure the interference. The transmitted beacons
that are
detected at the FSS sites thus enable the real-time measurement-based
propagation system
for closed loop control of interference, and thus the capability to share the
chosen spectrum
band (e.g., the C-band). Specific embodiments of these beacon detection
systems are
described in greater detail as follows.
[00360] In an exemplary embodiment, the design and implementation of
the beacon detection architecture at each earth station site is accomplished
by one or more
of several types of individual detectors, and according to one or more various
implementation processes. In some embodiments, one or more of the following
detector
types and implementation processes are utilized together for additional
accuracy and
reliability of interference measurements, calculations, and mitigation, and
also for the ease
of integrating separate infrastructures as the present systems and methods are
scaled
upward to accommodate more sites.
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[00361] FIG. 19 is a schematic illustration of an FSS site 1900 configured
to implement protection scheme 400, FIG, 4. In the exemplary embodiment, FSS
site 1900
includes one or more earth stations 1902, and one or more of a platform-
mounted beacon
receiver 1904, a station-integrated beacon receiver 1906, a co-located beacon
receiver
1908, and an auxiliary beacon receiver 1910. Earth stations 1902 are, for
example, similar
to earth stations 504, FIG. 5, and the several beacon receivers 1904, 1906,
1908, 1910
(sometimes referred to as "BR" or "BRs"), may be each configured to perform
the
functionality of beacon detector 528 at FSS site 502.
[00362] In exemplary operation of FSS site 1900, each of beacon
receivers 1904, 1906, 1908, 1910 are further configured to receive beacon
transmissions
from one or more beacon transmitters 1912, such as may be disposed at or near
an AP (not
shown) or a UE (also not shown). In this example, beacon transmitters 1912 are
similar in
form and function to beacon transmitters 518, FIG. 5. In further operation,
FSS site is
configured to communicate with a central server 1914. Central server 1914 is
thus similar
to central server/SAS 510, FIG. 5, and may communicate with FSS site 1900
according to
any one or more of the communication links described with respect to central
server/SAS
510.
[00363] In the exemplary embodiment, beacon receivers 1904, 1906,
1908, 1910 are located within, or in near proximity to, FSS site 1900 (i.e., a
cable operator
plant). Alternatively, one or more of beacon receivers 1904, 1906, 1908, 1910
are located
outside of FSS site 1900, but function in a similar manner (e.g., in
communication with
central server 1914 from a remote location). Additionally, the present
embodiments are
described with respect to the 4 GHz portion of the C-band, as well as the 6
Ghz spectrum;
however, the systems and methods described herein are further advantageously
adaptable
to provide similar functionality for other spectral ranges that are utilized
in communication
systems that utilize the same, or similar, conventional system components
(e.g., earth
stations, satellite dishes, transmitters, receivers, APs, UEs, etc.), and/or
are capable of
being equipped with some or all of the beacon transmission/detection
infrastructure
described throughout this application.
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[00364] In an embodiment, FSS site includes one or more of each of
platform-mounted beacon receiver 1904, station-integrated beacon receiver
1906, co-
located beacon receiver 1908, and auxiliary beacon receiver 1910. In the
exemplary
embodiment depicted in FIG. 19, earth station 1902(1) includes platform-
mounted beacon
receiver 1904, earth station 1902(2) includes station-integrated beacon
receiver 1906, earth
station 1902(3) includes a single co-located beacon receiver 1908, and earth
station
1902(4) includes a plurality of co-located beacon receivers 1908. In this
example, FSS site
1900 further includes a plurality of auxiliary beacon receivers 1910, which
may be similar
to distributed detector 548, FIG. 5.
[00365] FSS site 1900 thus represents a distributed beacon receiver
system, where the several beacon receivers 1904, 1906, 1908, 1910 are
distributed at or
among earth stations 1902 to capture beacon transmission signals from remote
beacon
transmitters 1912 and report information, such as the beacon power, beacon ID,
and the
status of the respective beacon receiver to central server 1914 to enable
central server 1914
to estimate the potential interference. According to this advantageous
embodiment, the
potential interference may be estimated both at the single FSS site 1900, and
also at all FSS
sites within range of a beacon-transmitting AP. Through implementation of this
advantageous infrastructure, central server 1914 is further capable of
coordinating
interference-free FSS operation across all of the FSS sites within range. In
exemplary
implementation, a particular beacon receiver may be disposed with respect to
earth station
1902 of FSS site 1900 by (i) mounting (e.g., platform-mounted beacon receiver
1904), (ii)
integrating (e.g., station-integrated beacon receiver 1906), (iii) co-locating
(e.g., co-located
beacon receivers 1908), and/or (iv) auxiliary placement (e.g., auxiliary
beacon receivers
1910).
[00366] FIG. 20 is a schematic illustration of a beacon detection system
2000 that implements earth station 1902(1) and platform-mounted beacon
receiver 1904,
FIG. 19. Platform-mounted beacon receiver 1904 is an optional, or
supplemental,
configuration to the several beacon receiver configurations described herein
(e.g., beacon
receivers 1906, 1908, 1910). According to beacon detection system 2000,
platform-
mounted beacon receiver 1904 may be directly mounted to a fixed component of
earth
station 1902(1). In the exemplary embodiment, platform-mounted beacon receiver
1904 is
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fixed to earth station 1902(1) at a position proximate an antenna feed socket
2002 (i.e., near
the focal point of a reflector 2004). From this exemplary location, platform-
mounted
beacon receiver 1904 is able to share the antenna gain, and thus also the
received power,
similar to the respective gain and power that will be observed at a feed horn
2006. Feed
horn 2006 may be, in this example, similar to feed horn 208, FIG. 2. In this
example,
platform-mounted beacon receiver 1904 is similar to integral beacon detector
528(1), FIG.
5.
[00367] According to one or more of the calibration techniques described
above, platform-mounted beacon receiver 1904 is able to measure the beacon and
associated potential interference level approximate to a level at a reference
point 2008
between an RRF 2010 and an LNB 2012.
[00368] In exemplary operation of beacon detection system 2000, the
power level Põf (in dB) may be calculated at reference point 2008 according
to:
Pref = PBR 'cat (Eq. 1)
[00369] where PBR represents the measured power at platfolin-mounted
beacon receiver 1904 with an equivalent isotropic antenna and a 0-dB gain, and
Pcat
represents a calibration factor. In exemplary operation, each platform-mounted
beacon
receiver 1904 is configured to submit the measured data, including, for
example, Põf
and/or PBR, satellite antenna gain (or dish parameters), and/or the FH or RRF
losses to the
central server (e.g., central server 1914, FIG. 19), that is, in some cases,
Põf represents a
sum of PBR P
- BR¨measured, where P
- BR¨measured = PBR G ainreflector =
[00370] FIG. 21 is a schematic illustration of a beacon detection system
2100 that implements earth station 1902(2) and station-integrated beacon
receiver 1906,
FIG. 19. In this example, station-integrated beacon receiver 1906 represents
an alternative
embodiment of integral beacon detector 528(1), FIG. 5. In an embodiment,
implementation of station-integrated beacon receiver 1906 at a particular
earth station 1902
(e.g., earth station 1902(2)) advantageously enables protection of the
particular FSS site
without additionally requiring implementation of platform-mounted beacon
receiver 1904,
co-located beacon receiver 1908, or auxiliary beacon receiver 1910.
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[00371] According to beacon detection system 2100, station-integrated
beacon receiver 1906 is tapped into a link 2102 between an LNB 2104 and a
satellite signal
receiver 2106. Through this integration of station-integrated beacon receiver
1906 into link
2102, a measurement may be obtained which includes the exact antenna gain and
the link
attenuation before a reference point 2108. According to this exemplary
architecture, the
hardware design of station-integrated beacon receiver 1906 may be greatly
simplified in
comparison with directly-mounted designs, because the sensitivity requirements
of the
receiver were significantly relieved due to the ability to share components,
such as LNB
2104. In an embodiment, beacon detection system 2100 further includes an RRF
2110 and
a feed horn 2112. In at least one embodiment, this configuration is realized
through
utilization of a spare LNB that is not presently in use by system 2100, or
alternatively,
through installation of a large LNB array.
[00372] In exemplary operation of beacon detection system 2100, the
power level Pref may be calculated at reference point 2108 according to:
Pref = PBR GLNB A (Eq. 2)
[00373] where GLNB represents the gain of LNB 2104, and A represents
the attenuation and insertion loss of a portion 2114 of link 2102 between LNB
2104 and
station-integrated beacon receiver 1906. In exemplary operation, each station-
integrated
beacon receiver 1906 is configured to submit the measured data, including, for
example,
Prep PBR, the satellite antenna gain (or dish parameters), and/or FH and RRF
losses to the
central server (e.g., central server 1914, FIG. 19).
[00374] In the exemplary embodiment depicted in FIG. 21, station-
integrated beacon receiver 1906 is illustrated to be disposed after LNB 2104
(i.e., with
respect to each particular dish utilizing beacon receiver 1906), but before
satellite signal
receiver 2106, and tapped at link 2102. Through this advantageous
configuration, station-
integrated beacon receiver 1906 is capable of directly measuring the
interference at the
particular dish (or each utilizing dish). The received beacon signal will thus
directly
experience the same satellite antenna gain as will the signal for any
direction. This
advantageous configuration would require little or no calibration, and may be
simply
installed with respect to existing conventional infrastructures through use of
a tap after
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LNB 2104, and would therefore involve no significant interruption to the
service by this
type of installation. Other types of beacon receiver configurations may
individually vary
with respect to the accuracy of measurements, the cost of installation, and
the required
calibration, but may nevertheless provide particular advantages depending on
the actual
considerations experience that an individual FSS site.
[00375] In some embodiments, at least one steerable beacon detector is
disposed externally to an FSS site, and may operate as a single beacon
receiver for several
dishes at the particular site, aunt/or for other sites within the operational
range. In this
example, the steerable beacon detector may be configured to have a higher
antenna gain
than the FSS site itself, particularly in the case of small diameter dishes
being used at the
FSS site. In practice, conventional 2-m dishes have high gains of
approximately 37 dBi,
which is generally higher than the gain of such an external steerable antenna.
Nevertheless,
the present embodiments contemplate utilizing higher-gain narrow-beam antennas
to
increase the link budget for beacon detection, which may be steerable, for
example, using
MIMO.
[00376] Although use of such external beacon receivers might increase the
cost or complexity of the overall system in some other respects, the external
beacon
receivers may simultaneously also increase the size of the overall sensor
network for
interference measurements for calculations to build and improved the MBP
models of the
central server. Nevertheless, other APs may also include their own beacon
detectors,
thereby providing an alternative (or supplemental) technique to increase the
size of this
same sensor network
[00377] Referring back to FIG. 19, co-located beacon receivers 1908
represents an alternative, or supplemental in some embodiments, configuration
into either
or both of beacon detection system 2000, FIG. 20, and beacon detection system
2100, FIG.
21. As illustrated in FIG. 19, co-located beacon receivers 1908 are disposed
adjacent to,
but not connected directly with, and antenna system (not separately shown) of
the
respective earth station (e.g., earth stations 1902(3), 1902(4)). In at least
one embodiment,
one or more of beacon receivers 1908 are installed outside of the boundaries
of the
particular the FSS site, to obtain additional information for the MBP-based
propagation
model. According to this exemplary configuration, co-located beacon receivers
1908 may
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be individually steered toward a direction and position similar to the antenna
of the earth
station, such that an individual co-located beacon receiver 1908 may emulate a
spatial
response similar to that of the antenna.
[00378] In some embodiments, steerable antennas having narrow-beam
and high-gain functionality are utilized to detect beacons instead of (or in
addition to) the
radar system infrastructures described herein. For example, the respective
satellite dishes
of such steerable antennas may enable increases to the link budget for the
beacon detection
system, due to the higher gains thereof. In one example, each FSS site may
include at least
one steerable antenna per site, and the central server thereof may be further
configured to
build and dynamically update a model based on the inter-detected beacon
interference to
each FSS at the particular FSS site.
[00379] In exemplary operation, co-located beacon receivers 1908 are
configured such that the power level Põf at reference point (not shown with
respect to co-
located beacon receiver 1908) of the respective earth station 1902(3), 1902(4)
may be
calculated or estimated according to:
Pref = PBR Gant(e) 0.5 (Eq. 3)
[00380] where G ant (0)represents the measured antenna gain (in dB) of the
antenna of the respective earth station 1902(3), 1902(4) in the corresponding
direction 0 of
the detected beacon transmitter (e.g., beacon transmitter 1912, FIG. 19), and
where PBR is
expressed in dBm and the 0.5 value represents an RRF loss of 0.5 dB. In the
exemplary
embodiment, the direction 0 is determined from the respective locations of the
beacon
transmitters and earth station 1902(3) or 1902(4). In some embodiments, the
direction 0
may be affected by the elevation and azimuth angles of earth station 1902(3)
or 1902(4).
In an embodiment, a nominal value for antenna gain Gant(0) may also be
calculated, e.g.,
according to FCC 25.209(a), if the actual measured data of the antenna is
unavailable. In
at least one embodiment, the measured value PBR is, for example, an average
value, or may
represent a combination of measured values from multiple co-located beacon
receivers
1908 where a plurality are disposed proximate an individual earth station,
such as earth
station 1902(4). In at least one embodiment, the measured value PBR is
obtained using a
high-gain antenna.
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[00381] Similar to the embodiments described above with respect to
beacon detection systems 2000, 2100, each co-located beacon receiver 1908 may
be
configured to submit the measured data, including, for example, the single or
combination
value for Põf and/or PBR, to the central server (e.g., central server 1914,
FIG. 19).
[00382] With reference to Eq. 3, above, the calculated power level might
deviate from the true level at the respective reference point. In such cases,
this deviation
may not be possible to correct through calibration techniques, due to the
physical
separation between co-located beacon receiver 1908 and the respective earth
station
1902(3) or 1902(4), and the associated variation and uncertainty of the power
level over
space. Such variation and uncertainty might be particularly severe at earth
station sites that
include metallic facilities sufficient to cause strong multi-path effects
and/or power fading.
Where such difficulties are encountered, the systems and methods described
herein may be
further advantageously configured to deploy one or more auxiliary beacon
receivers 1910
throughout FSS site 1900, or to implement a simplified configuration at each
individual
dish according to system 2100.
[00383] Therefore, according to this exemplary auxiliary configuration, a
plurality of auxiliary beacon receivers 1910 may be distributed throughout FSS
site 1900
and function to advantageously provide additional, but separate, measured
samples for
estimating the power levels at earth stations 1902 equipped with a mounted, an
integrated,
and/or a co-located detector. In the exemplary embodiment, auxiliary beacon
receivers
1910 further serve to function to provide a power level estimate for an earth
station that
does not include its own beacon detector, or at least one of the mounted,
integrated, or co-
located embodiments described above.
[00384] In at least one embodiment, a plurality of auxiliary beacon
receivers 1910 are disposed such that they surround earth stations 1902 at
various and/or
random locations where power and/or an Internet connection is available, but
which may
not be readily available or easily accessed by a particular earth station
1902. Through this
advantageous configuration, earth stations 1902 may located and positioned to
receive
optimal satellite transmission signals, even if such locations are not optimal
to measure
potential interference or communicate with the central server.
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[00385] In exemplary operation of auxiliary beacon receivers 1910, the
power level Pref at reference points of respective earth stations 1902 may be
calculated in
several ways. In a first example, a maximal value max{PBR,i) is selected from
data
obtained from co-located beacon receivers 1908 and a subset of the surrounding
auxiliary
beacon receivers 1910 within a predetermined range, according to:
Põf = max[PBRA. + Gant(0) ¨ 0.5 (Eq. 4)
[00386] In a second example, the power level Põf is obtained using the
mean of the power collected from these co-located beacon receivers 1908 and
auxiliary
beacon receivers 1910, with a total number of N, according to:
N
'ref = ¨NEi ci PBR,i Gant(0) ¨ 0.5 (Eq. 5)
[00387] where ci represents a coefficient for the i-th beacon receiver, in
the case where different beacon receivers have different weights. In an
embodiment, the
coefficient ci may be derived from a previous calibration and/or training
techniques during
operation.
[00388] In a third example, the power level Põf is obtained using
interpolation, e.g. Kriging interpolation, based on the location and elevation
of the earth
station antenna, as well as the respective power levels, locations, and
elevations of a subset
of the surrounding auxiliary beacon receivers 1910 within the predetermined
range.
Similar to the embodiments described above, each auxiliary beacon receiver
1910 may also
be configured to submit the measured data, including, for example, its own
PBR, to the
central server (e.g., central server 1914, FIG. 19). Alternatively, an
individual auxiliary
beacon receivers 1910 is configured to submit data to a different auxiliary
beacon receiver
1910 belonging to the same subset, and this different auxiliary beacon
receiver 1910 may
then submit the combined result Põf to the central server.
[00389] FIG. 22 is a schematic illustration of a distributed antenna system
(DAS) 2200 configured to implement protection scheme 400, FIG. 4. In the
exemplary
embodiment, DAS 2200 may be deployed in addition, or as an alternative, to
each of the
four embodiments of beacon receivers 1904, 1906, 1908, 1910 described above.
That is,
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the at least one embodiment, DAS 2200 is deployed as a substitute for the
distributed
beacon detection architectures described above.
[00390] In an exemplary embodiment, DAS 2200 includes a central
beacon receiver 2202 and a plurality of remote antennas 2204 distributed
throughout an
FSS site (e.g., FSS site 502, FIG. 5), with each remote antenna 2204 having at
least one
operable communication connection with central beacon receiver 2202. In some
embodiments, DAS 2200 further includes one or more remote beacon receivers
2206,
according to the embodiments described above. In exemplary operation, central
beacon
receiver 2202 collects received signals from remote antennas 2204, and may be
further
configured to derive the power level PBR that applied onto the respective
reference point of
an earth station 2208.
[00391] In a first example, the power level PBR is obtained by selecting
the maximal value maxtPano} from the plurality of remote antennas 2204,
according to:
PBR max{Pant,i} (Eq. 6)
[00392] where Parit,i represents the measured power at the i-th remote
antenna 2204 with an equivalent isotropic antenna and a 0-dB gain over the
link of DAS
2200.
[00393] In a second example, the power level PBR is obtained using the
mean of the power collected from a total number M of remote antennas 2204,
according to:
[00394] -PBR = ¨ml Erd Pant,i (Eq. 7)
[00395] where di represents a coefficient for the i remote antenna 2204.
Similar to coefficient ci, described above, the coefficient di may also be
derived from a
previous calibration and/or training techniques during operation. In further
operation of
DAS 2200, the results obtained from Eq. 6 or Eq. 7 are applied to the
calculation
represented by Eq. 3 to derive the power level at the respective reference
point.
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[00396] The advantageous configuration of DAS 2200 realizes further
benefits of being able to implement conventional DAS schemes with respect to
the
innovative beacon detection and decoding embodiments described herein. In an
exemplary
operation, a maximal ratio combining (MRC) mechanism is used upon signals from
remote
antennas 2204 before correlating a subject beacon ID from a particular beacon
transmitter j
(e.g., beacon transmitter 1912, FIG. 19), according to:
c=N
hix.Xi
XBR,J = N ____________________ 2 (Eq. 8)
[00397] where xi represents a signal vector collected at the i remote
antenna 2204, hij represents a channel response from the j beacon transmitter
to the i
remote antenna 2204, and estimated using a priori information, or from a
previous
measurement. The derivation value XBRJ may then be used for succeeding
receiver
processing, such as correlation with the reference beacon signal from the j
beacon
transmitter. In the exemplary configuration of DAS 2200, each of remote
antennas 2204,
as well as RF filters or related components (not shown) are implemented to
follow the
relevant descriptions in FCC part 25 and part 96. In each of the foregoing
embodiments,
the individual techniques and configurations of the several different beacon
detection
alternatives (i.e., mounted, integrated, co-located, auxiliary, DAS) may be
advantageously
implemented alone, or in any combination with each of the other alternatives.
DIRECTIONAL AND MULTI-ANTENNA SYSTEMS FOR IN-BAND PROTECTION
[00398] The present embodiments are further of particular advantageous
use with respect to the operation of directional-antenna and multiple antenna
(also referred
to herein as "multi-antenna") mobile communication systems, and specifically
for
minimizing the interference to and from satellite systems that operate in the
same or
adjacent frequency band. The following embodiments may be employed with one or
more
of the beacon transmission systems and methods described above, whether in
whole or in
part.
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[00399] As described above, mobile communication systems presently
coexist with satellite communication systems in the same CBRS band. Some
recent mobile
communication proposals seek to liberate spectrum for flexible use within the
3.7-4.2 GHz,
5.925-6.425 GHz, and 6.425-7.125 GHz bands. The 3.7-4.2 GHz band, for example,
includes 12 channels on each polarization, which are primarily used for the
downlink (i.e.,
from space to earth) of satellite communication systems. There are thousands
of earth
stations operating in this band in the US, and these earth stations require
interference
protection. At present, the FCC regulates the interference levels from
services sharing the
same band. Interference considerations may not be the same in the 6 GHz bands
though,
since the satellite uplink does not have the sensitivity of the downlink.
Nevertheless, very
close proximity that is typically seen between satellite transmitters may
still give rise to
particular protection needs.
[00400] Macro-cellular deployment for mobile use within these spectra
will generally create interference to FSS sites that use the C-band downlink,
due to the
lower propagation loss above clutter (i.e., relative to below clutter), as
well as from the use
of significantly higher transmitter powers in comparison with that of small
cell use. At
present, the protection distances between a macrocell and an FSS site tend to
be
considerably large, and exacerbated by MI1\40 antenna implementations, which
effectively
enhance the gain of the base station and increase the spectral density
thereof. The present
systems and methods mitigate these obstacles considerably in mobile use cases,
as
described herein. Nevertheless, some of these embodiments may be of even
further
advantageous use with respect to fixed wireless access (FWA) implementations
in light of
the speed of beam-forming across a mobile network. In some countries, the use
of the 3.7-
4.2 GHz spectrum is confined to limited geographical regions without
widespread
distribution of FSS. In such cases, it may be more desirable to allow use of
the C-band for
mobile implementations, and fixed radio use elsewhere. In some of these cases,
however,
interference may still occur in boundary regions between these geographical
areas, in
which case a buffer region may be created between the two usage systems (e.g.,
minimized
to enhance microcellular mobile coverage).
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[00401] Multi-antenna technologies, such as MIMO and massive MIMO,
are known to increase spectral efficiency by providing multiplexing gain, and
to improve
SNR by providing diversity gain. Multi-antenna and technology is therefore of
particular
utility with respect to emerging communication technologies, such as 5G. Multi-
antenna
systems support multiple users/multi-user, as well as high-resolution
beamforming
(sometimes labeled as "BF"). Beamforming is conventionally implemented in
existing
communication standards, such as coordinated multipoint (CoMP) in LTE for
interference
mitigation. Multi-antenna transmission is considered to be capable of
maximizing the
power level at a particular location by beamforming techniques, or minimizing
the power
level by the related null forming (sometimes labeled as "NF") techniques.
[00402] With respect to FWA implementations using the 3.7-4.2 GHz C-
band, such as in 5G, MIMO-based systems may be particularly useful in rural
areas, where
the density of surrounding FSS sites would be expected to be considerably
lower than it
would be in higher populated areas. With FWA specifically, the number of
connected
locations is expected to be significantly lower than with a mobile use case.
[00403] As also described above, conventional coexistence techniques do
not use the beacon infrastructure described herein, and are primarily based on
propagation
modeling, priority tiers, protection zones, and radio sensing. As described
further below,
the present systems and methods may be advantageously configured to implement
an
innovative auxiliary beacon infrastructure onto even conventional mobile
communication
systems. The present embodiments are thus further capable of being configured
to use
directional and multi-antenna technology, and also implement advantageous
techniques
that enable greater control of the signal pattern radiated from (or received
at) the particular
mobile communication system. This radiated signal pattern may then be managed
to cause
minimal interference at the satellite system/mobile communication system,
thereby
reducing the protection distance between the system and the FSS site. This
consideration
could be particularly useful, for example, where it is desirable to reduce the
size of the
buffer area or where there is a low density of FSS sites surrounding a
macrocell size.
[00404] FIG. 23 is a schematic illustration of a multiple-antenna shared-
use system 2300. Shared-use system 2300 may include, or be utilized in a
complementary
fashion with, one or more of the several embodiments described above. In an
exemplary
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embodiment, shared-use system 2300 includes an earth station 2302 and a
plurality of LTEs
2304 (e.g., or fixed transceivers, as in the case of FWA) in proximity one or
both of a first
antenna system 2306 and a second antenna system 2308. In the example depicted
in FIG.
23, first antenna system 2306 represents a communication system AP (e.g.,
mobile, FWA,
etc.) equipped with a multi-antenna wireless transceiver, and second antenna
system 2308
represents a communication system AP equipped with a directional antenna.
[00405] In one embodiment, such as an FWA use case where an FSS site
is located behind a receiving home direction, use of a null might disconnect
this location.
In such cases, a MESH network interconnecting homes, may be implemented in a
cooperative manner with the present embodiments, thus lowering the number of
communication links.
[00406] In exemplary operation of system 2300, first antenna system 2306
generates a first beam pattern 2310, and second antenna system 2308 generates
a second
beam pattern 2312. As depicted in FIG. 23, first beam pattern 2310 from the
multi-antenna
transceiver of first antenna system 2306 radiates one or more spatial radio
beams (also
referred to herein as beamforming, or BF, herein) 2314 for spatial high-gain
UE or FWA
coverage (e.g., UEs 2304(1), 2304(2)), while forming a null 2316 (also
referred to as null
forming, or NF, herein) to mitigate radiation in a first direction 2318 toward
earth station
2302. In contrast, second beam pattern 23 12 from the directional antenna of
second
antenna system 2308 is more uniform and generates minimal radiation in a
second
direction 2320 toward earth station 2302.
[00407] FIG. 24 illustrates a far field beam pattern 2400 for a multiple
antenna system 2402. Far field beam pattern 2400 is similar to first beam
pattern 2310,
FIG. 23, of first antenna system 2306, except that multi-antenna system 2402
is configured
to utilize beamforming to radiate a plurality of radio beams (BFs) 2404 in
multiple
directions about multiple antenna system 2402, such that beam pattern 2400
results in the
far field shape depicted in FIG. 24.
[00408] FIG. 25 is a schematic illustration of a multiple antenna system
2500. System 2500 includes at least one multi-antenna transceiver array 2502
and a field
beam pattern 2504 radiating a plurality of high-gain radio beams 2506 toward
respective
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UEs 2508 or FWA transceivers. FIG. 26 is a schematic illustration of a
multiple antenna
system 2600. System 2600 includes at least one multi-antenna transceiver array
2602 and a
field beam pattern 2604 which forms a plurality of nulls 2606 directed toward
respective
earth stations 2608. Earth stations 2608 may be similar to earth station 2302,
FIG. 23.
Multi-antenna transceiver 2602 may be similar in structure to multi-antenna
2502, FIG. 5.
[00409] Conventional coexistence technology utilizes BF to provide better
coverage for UE sets (e.g., FIG. 25), or to minimize the interference inside
the mobile
network of system 2500. The innovative systems and methods described herein
though,
are additionally configured and programmed to further operate the respective
antenna
arrays to provide the plurality of nulls 2606 toward and/or from respective
earth stations
2608 (e.g., FIG. 26), and also to extend the use case to FWA. The underlying
structures
and operations of systems 2500 and 2600 are described further below with
respect to
various combinations thereof in the following multiple antenna systems. In the
following
embodiments, the various UEs are depicted for illustration purposes to
represent respective
mobile communication subsystems or FWA transceivers, and various earth
stations are
depicted for similar purposes, namely, to represent respective satellite
subsystems.
[00410] FIG. 27 is a schematic illustration of a multiple antenna system
2700. Similar to FIGS. 25 and 26, above, system 2700 also includes at least
one multi-
antenna transceiver array 2702 configured to generate a beam pattern 2704.
Unlike
conventional systems, multi-antenna transceiver array 2702 may be
advantageously
configured to generate a far field beam pattern 2706, and also to implement
both BF and
NF. In some cases, array 2702 implements BF and NF simultaneously. In the
exemplary
embodiment, beam pattern 2704 includes a plurality of high-gain radio beams
2706
directed toward a plurality of mobile subsystems 2708 (e.g., including UEs),
respectively.
In a similar, but complementary, manner, beam pattern 2704 further includes a
plurality of
nulls 2710 directed toward respective satellite subsystems 2712 (e.g.,
including earth
stations).
[00411] In exemplary operation of system 2700, array 2702 is configured
to implement both BF and NF to protect a satellite downlink 2714 to satellite
subsystems
2712 from a mobile downlink 2716 of mobile subsystems 2708. That is, in order
to protect
satellite downlink 2714 from mobile downlink 2716, operation of array 2702 is
configured
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to establish both BF and NF at substantially the same time for transmission of
mobile
downlink 2716 in a cell (e.g., beam pattern 2704) covered by multiple antenna
system
2700. In the exemplary embodiment, beams 2706 and nulls 2710 are generated
from the
same mechanism (e.g., a central processor (not shown) cooperating with array
2702).
According to this example, using the MBP techniques described above, the
respective
beams 2706 and nulls 2710 may be further optimized for both improved LTE/FWA
coverage and satellite protection. In a case where transmission of a beacon
from a base
station is problematic, one contemplated remedy would be a change in the
frequency of
operation.
[00412] In at least one embodiment of system 2700, the BF and NF
operations may each further consider the channel status and system
information. For
example, as illustrated in FIG. 27, the satellite subsystem farthest from
array 2702 (satellite
subsystem 2712(1) in this example) may require less NF attenuation than a
satellite
subsystem farther away (satellite subsystem 2712(2) in this example), as
indicated by null
2710(1) being substantially smaller than null 2710(2). This use case may be
particularly
advantageous, for example, in FWA and SG implementations.
[00413] In one example of system 2700, the base station may be on the
same frequency as the satellite ground station. In such cases, system 2700 may
be
implemented in a complementary fashion with a stoplight system, e.g.,
stoplight system
3800, FIG. 38 (described further below) to more reliably eliminate significant
interference
at the ground stations with a means of identification. A stoplight system may
further serve
to improve the successful implementation of the MBP techniques described
above.
Nevertheless, according to the BF and NF principles of system 2700, the base
station
location may be significantly closer than conventionally seen, thus enabling
better coverage
and capacity within the cellular network.
[00414] FIG. 28 is a schematic illustration of a multiple antenna system
2800. System 2800 may be similar to system 2700, FIG. 27, in overall
architecture and
general functionality. That is, system 2800 may include at least one multi-
antenna
transceiver array 2802 configured to generate a beam pattern 2804 implementing
at least
BF, and including a plurality of beams 2806 respectively directed toward a
plurality of
mobile subsystems 2808. System 2800 differs from system 2700 though, in that
system
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2800 illustrates a case for protecting a respective satellite downlink 2810 of
a satellite
subsystem 2812 from a mobile uplink transmission 2814 from one or more of
mobile
subsystems 2808. In this exemplary embodiment, as well as the several
following
embodiments, "mobile" may be considered to refer to both mobile and FWA
transceivers.
[00415] More particularly, in exemplary operation of system 2800,
beamforming is established for mobile/FWA uplink transmission 2814 within the
cell
covered by beam pattern 2804, such that the SNR in the uplink from respective
UEs or
FWA transceivers of mobile subsystem(s) 2808 may be adjusted and/or optimized
at a
receiver portion (not separately shown) of multi-antenna transceiver array
2802 using a
minimal transmitted power from the respective UEs. It may be noted in this
particular
example, that because protection is only sought for satellite downlink 2810
from mobile
uplink transmission 2814, it is not necessary to consider NF techniques for
forming nulls in
this particular embodiment.
[00416] FIG. 29 is a schematic illustration of multiple antenna system
2900. In the exemplary embodiment, system 2900 is similar to system 2700, FIG.
27, in
architecture and functionality, and may include at least one multi-antenna
transceiver array
2902 configured to generate a beam pattern 2904 implementing both BF and NT,
which
includes a plurality of beams 2906 respectively directed toward a plurality of
mobile
subsystems 2908, as well as a plurality of nulls 2910 directed toward
respective satellite
subsystems 2912. System 2900 differs from system 2700 though, in that system
2900
illustrates a case for minimizing interference to a mobile uplink transmission
2914 of
mobile subsystems 2908 from a respective satellite uplink 2916 of one or more
satellite
subsystems 2912.
[00417] More particularly, in exemplary operation of system 2900, both
BF and NF are established in the cell covered by multi-antenna transceiver
array 2902 for
mobile uplink transmission(s) 2914 within the cell. In at least one embodiment
of system
2900, the BF and NF operations may each further consider the channel status
and system
information, similar to system 2700, FIG. 27. Also similar to system 2700, as
illustrated in
the example depicted in FIG. 29, the satellite subsystem farthest from array
2902 (satellite
subsystem 2912(1) in this example) may require less NF attenuation than a
satellite
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subsystem farther away (satellite subsystem 2912(2) in this example), as
indicated by a first
null 2918 being substantially smaller than a second null 2920.
[00418] FIG. 30 is a schematic illustration of a multiple antenna system
3000. System 3000 may be similar to system 2800, FIG. 28, in architecture and
functionality. That is, system 3000 may include at least one multi-antenna
transceiver
array 3002 configured to generate a beam pattern 3004 implementing at least
BF, which
includes a plurality of beams 3006 respectively directed toward a plurality of
mobile
subsystems 3008. System 3000 differs from system 2800 though, in that system
3000
illustrates a case for minimizing interference to a mobile downlink
transmission 3010 to
mobile subsystems 3008 from a respective satellite uplink 3012 of one or more
satellite
subsystems 3014.
[00419] More particularly, in exemplary operation of system 3000,
beamforming is established for mobile downlink transmission 3010 within the
cell covered
by beam pattern 3004, such that the downlink SNR from multi-antenna
transceiver array
3002 may be maximized at the respective UEs of mobile subsystems 3008. It may
be
noted in this particular example, that because protection is only sought for
mobile downlink
3010 from satellite uplink transmission 3012, it is not necessary to consider
NF techniques
for forming nulls in this particular embodiment.
[00420] FIG. 31 is a schematic illustration of a mobile network 3100
implementing joint beamforming and null forming. In an exemplary embodiment,
mobile
network 3100 includes at least one satellite subsystem 3102, at least one
mobile subsystem
3104, a first multiple antenna communication cell 3106 (CELL #1), and a second
multiple
antenna communication cell 3108 (CELL #2). Each of first and second
communication
cells 3106, 3108 may be similar to the cells described in the embodiments
above, and
include at least one respective multi-antenna transceiver array 3110, each of
which may be
configured to implement both BF and NF.
[00421] In an exemplary operation of mobile network 3100, BF and NF
are established based on the global condition of mobile network 3100, and
jointly managed
according to the innovative techniques described herein. That is, in practice,
a plurality of
multi-antenna communication systems (e.g., first and second communication
cells 3106,
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3108) may jointly provide desired coverage for one or more UEs or FWA
transceivers of
mobile subsystem 3104, while also providing protection to (and from) satellite
subsystem(s) 3102. In this embodiment though, the joint operation of cells
3106, 3108 is
configured to manage the operation of each cell in consideration of the other
cell.
[00422] For example, as depicted in FIG. 31, joint operation of cells 3106,
3108 may initially establish NF for each cell in regard to the other. In this
example, in a
direction of second cell 3108, first cell 3106 forms a first null 3112 in a
first beam pattern
3114 of first cell 3106. Similarly, in a direction of first cell 3106, second
cell 3108 foul's a
second null 3116 in a second beam pattern 3118 of second cell 3108. A joint
effect of first
and second nulls 3112, 3116 between the respective cells 3106, 3108 serves to
minimize
inter-cell interference therebetween. In further operation of system 3100,
first cell 3106 is
configured to additionally form a third null 3120 in first beam pattern 3114
in the direction
of satellite subsystem 3102, and second cell 3108 is configured to
additionally form a
fourth null 3122 in second beam pattern 3118, also in the direction of
satellite subsystem
3102.
[00423] In this example, because the second cell 3108 is depicted to be
farther away from satellite subsystem 3102 than is first cell 3106, fourth
null 3122 is
illustrated to be somewhat smaller than third null 3120, signifying a lower
need for
attenuation due to increased distance from potential interference. In still
further operation
of system 3100, first cell 3106 is additionally configured to establish BF
toward mobile
subsystem 3104, despite the existence of mobile subsystem 3104 (e.g., a UE
thereof)
between first cell 3106 and second cell 3108. That is, in the direction of
mobile subsystem
3104, first cell 3106 generates a radio beam 3124. In at least one embodiment,
first cell
3106 generates radio beam 3124 toward mobile subsystem 3104 even in the case
where a
UE of mobile subsystem 3104 is physically located within the transmission
boundaries of
second cell 3108.
[00424] Accordingly, in the example depicted in FIG. 31, it can be seen
that first null 3112 and radio beam 3124 in beam pattern 3114 distorted shape
to beam
pattern 3114 where null 3112 is superimposed with beam 3124. Similarly, it can
be seen
that second null 3116 and fourth null 3122 also form a distorted shape in beam
pattern
3118 from the superimposition thereof. As described above, this effect may be
different
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for mobile UEs (e.g., in a fast-moving vehicle), as compared with a fixed
transceiver of an
FWA subsystem. System 3100 is depicted, for ease of illustration, with respect
to a
satellite downlink 3126 of satellite subsystem 3102 and a mobile downlink
transmission
3128 from array 3110(1) of first cell 3106 to mobile subsystem 3104. However,
the person
of ordinary skill in the art will understand that the principles system 3100
fully apply also
in the case of a satellite uplink and/or mobile uplink, as described above in
the preceding
embodiments.
[00425] Through the innovative BF and NF techniques of system 3100
described herein, the respective superimposed pattern shapes of the cells may
be optimized
to achieve particular benefits over conventional systems, including without
limitation: (1)
maximal SNR, from the respective UEs, at the receiver (not shown in FIG. 31)
of multi-
antenna transceiver array(s) 3110; (2) maximal SNR, at the LTEs/FWA
transceivers, from
multi-antenna transceiver array(s) 3110; (3) minimal power, from multi-antenna
transceiver
array(s) 3110 and the UEs of mobile subsystem(s) 3104, at nearby satellite
subsystems
3102; and (4) minimal power, at multi-antenna transceiver array(s) 3110 and
the UEs of
mobile subsystem(s) 3104, from nearby satellite subsystems 3102. In an
exemplary
embodiment, operation of system 3100 is configured to optimize one or more of
the
preceding benefits according to predetermined criteria of the particular
system, and may
prioritize realization of one such benefit over another.
[00426] FIGS. 32A-C are schematic illustrations of a mobile network
3200 configured to implement dynamic null forming for different respective
frequencies.
In an exemplary embodiment, mobile network 3200 includes at least one multi-
antenna
transceiver array 3202 generating a beam pattern 3204. Beam pattern 3204
includes a first
null 3206 in a direction of a first satellite subsystem 3208 and a second null
3210 in a
direction of a second satellite subsystem 3212, In exemplary operation of
mobile network
3200, array 3202 is configured to implement dynamic NF in accordance with
changing
frequency channels transmitted by first and second satellite subsystems 3208,
3212.
According to this dynamic NF technique, mobile network 3200 is configured to
optimally
change the shape of beam pattern 3204 to provide a dynamic protection pattern.
In some
embodiments, network coordination and signaling are optimized to address
latency
concerns, and also with respect to the beacon transmissions described above.
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[00427] More particularly, according to the present embodiments, BF and
NF may both be established subject to the actual status of the respective UEs
or
mobile/FWA transceiver subsystems, satellite subsystems (e.g., subsystems
3208, 3212),
and the respective channels operated thereby. As illustrated above, that is,
through a
comparison of FIGS. 32A, 32B, and 32C, the NF shape of beam pattern 3204
changes over
time as the frequency channels of the respective satellite subsystems 3208,
3212 change.
In at least one embodiment, in the case of a fast-moving UE (e.g., a mobile
phone in a
moving automobile), the system may be configured to move the particular device
to a
different band.
[00428] Specifically, in this example, first and second nulls 3206A and
3210A have an initial shape when first and second satellite subsystems 3208,
3212,
respectively, are at initial frequency channels, as depicted in FIG. 32A. As
depicted in
FIG. 32B, when the frequency channel changes for second satellite subsystem
3212', the
shape of second null 321013 also changes in time in accordance with the
respective
frequency change. In this example, the frequency channel of first satellite
subsystem 3208
has not changed, and therefore there is no corresponding change to the shape
of first null
3206 (i.e., the shape of first null 32063 is substantially the same as the
shape of first null
3206A). As depicted in FIG. 32C, when the frequency channel changes for first
satellite
subsystem 3208', the shape of first null 3206c also changes in time (from the
shape of null
3206B) In this example though, the frequency channel of second satellite
subsystem 3212'
has not changed from the example of FIG. 32B, and therefore there is no
further
corresponding change to the shape of second null 3210 based only on the change
in the
shape of first null 3206 (i.e., the shape of second null 3210, is
substantially the same as the
shape of second null 32100.
[00429] FIG. 33 is a schematic illustration of a mobile or FWA network
3300 implementing channel estimation. In an exemplary embodiment, mobile
network
3300 includes at least one multi-antenna transceiver array 3302 generating a
beam pattern
3304. Beam pattern 3304 includes a plurality of nulls 3306 respectively formed
in
directions of a plurality of satellite subsystems 3308. In this example, beam
pattern 3304
further includes a plurality of radio beams 3310 respectively formed in
directions of a
mobile or FWA subsystems 3312. In the exemplary embodiment, each of satellite
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sub systems 3308 is equipped with a radio sensor 3314 (e.g., a beacon
detector, as described
above) within an FSS site of the respective subsystem 3308, or in operable
communication
therewith, in accordance with one or more of the embodiments described above
(e.g., co-
located, integrated, etc.).
[00430] In exemplary operation of mobile network 3300, a transmitter
(not separately shown) of multi-antenna transceiver array 3302 is configured
to transmit a
training symbol or beacon. In some embodiments, these transmitted
symbols/beacons are
sent at a relatively low power level, as described with respect to the beacon
infrastructure
systems and methods above, and optionally may or may not include information
pertaining
to the location of the respective satellite subsystem 3308, and/or nulls 3306
formed using
NF. Respective sensors 3314 are configured to be capable of detecting the
transmitted
training symbol(s)/beacon(s), thereby enabling mobile network 3300 (e.g., by a
processor
therein, or a central server in operable communication therewith) to derive
channel state
information (CSI) and feed the CSI back to array 3302 (e.g., a receiver
thereof, not
separately shown). In at least one embodiment, feedback to array 3302 is
performed
through backhaul facilities, such as a relay server (described further below
with respect to
FIG. 34) and/or over Ethernet.
[00431] After receiving the CSI feedback, multi-antenna transceiver array
3302 may be further configured to implement BF- and NF-encoding based on the
received
CSI. In the case where array 3302 includes a phase array multi-antenna system,
to realize
BF (e.g., for beams 3310), antenna phases (pi, (p2, (pN may be determined
according to:
[00432] argmaxy,,pz...vN lEi<i<N hiejtPil (Eq. 9)
[00433] where N represents the total number of antennas included in array
3302 (e.g., of an AP), and hi represents the channel response from an
individual antenna i
to the respective UE/mobile subsystem 3312.
[00434] Similarly, to realize NF (e.g., for nulls 3306), the antenna phases
(p2, (pN may be similarly determined according to:
[00435] argminvi,,p2...vN I Z1<i.,N (Eq. 10)
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[00436] where hi represents the channel response from the individual
antenna i to the respective satellite subsystem 3308.
[00437] FIG. 34 is a schematic illustration of a mobile network 3400
implementing satellite system information relay. In an exemplary embodiment,
mobile
network 3400 is similar to mobile network 3300, FIG. 33, and includes at least
one multi-
antenna transceiver 3402 generating a beam pattern 3404, which includes a
plurality of
nulls 3406 respectively formed in directions of a plurality of satellite
subsystems 3408. In
this example, beam pattern 3404 further includes a plurality of radio beams
3410
respectively formed in directions of a plurality of mobile subsystems 3412. In
the
exemplary embodiment, mobile network 3400 is in operable communication with a
server
33 14 (e.g., a central server or SAS, described above) configured to collect
information
from satellite subsystems 3408 and sensors thereof (e.g., sensor 3314, FIG.
33), which may
include without limitation the respective locations, frequency channels,
angles, antenna
gains, site conditions, CSI, etc.
[00438] In exemplary operation of multiple network 3400, server 3314
executes a collection operation 3416 of some or all of the information from
respective
satellite subsystems 3408, and then executes a relay operation 3418 of the
collected
information to a receiving portion (not separately shown) of multi-antenna
transceiver
3402. In some embodiments, the relayed information may be further relayed (not
shown in
FIG. 34) from transceiver 3402 to respective mobile subsystems 3412 (e.g., UEs
including
thereof). In at least one embodiment, server 3414 is further configured to
provide
additional information, including without limitation, geographic information
and/or
building layouts, to mobile network 3400 to further facilitate BF and NF
operation.
[00439] FIG. 35 is a flow diagram of an exemplary process 3500 for
operating a multiple antenna system. In an exemplary embodiment, process 3500
may be
implemented with respect to one or more of the embodiments depicted in FIGS.
23-34. In
operation, process 3500 begins at step 3502, in which a grant is received from
a server for
an AP to transmit (e.g., step 620, FIG. 6). In an exemplary embodiment of step
3502, the
grant is received after management by a stoplight system (e.g., FIG 38,
below). In step
3504, a multi-antenna receiver receives status information of one or more
satellite
subsystems/earth stations adjacent or approximate to the respective AP. Upon
completion
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of step 3504, process 3500 proceeds to execute one or both of beamforming
subprocess
3506 and null forming subprocess 3508.
[00440] Beamforming subprocess 3506 begins at step 3510, in which the
multiple antenna system obtains location information for one or more UEs
operating within
the range of a cell of the system. In an exemplary embodiment of step 3510,
collection of
UE locations is facilitated utilizing one or more other communication systems
belonging to
the same heterogeneous network. Step 3512 is a decision step. In step 3512,
process 3500
determines if transmission to/from a particular UE or FWA location is "safe,"
that is, may
be performed without unreasonable interference from/to a particular FSS site.
If, in step
3512, process 3500 determines that a particular UE or FA location is not safe,
process 3500
proceeds to step 3514, in which communication with the particular UE at that
location is
disabled, and process 3500 then returns to step 3510. If, however, in step
3512, process
3500 determines that the UE a location is safe, process 3500 proceeds to step
3516.
[00441] In step 3516, the server and/or the multi-antenna receiver obtains
CSI for at least one UE at location determined to be safe. In step 3518,
process 3500
implements beamforming from the multi-antenna transmitter in the direction of
the UE for
which CSI was obtained in step 3516. Null forming subprocess includes a step
3520, in
which process 3500 implements null forming in the direction of the location(s)
of one or
more earth stations obtained in the status information received in step 3504.
The
exemplary embodiment described with respect to FIG. 35 is provided for
illustration
purposes, and is not intended to be limiting. For example, symmetric and/or
similar
operations, steps, subprocesses, etc. may be alternatively, or additionally,
implemented for
UEs in the case of UEs being equipped with multi-antenna transceivers. In such
instances,
BF and NF may, for example, be jointly processed with multiplexing mode.
[00442] FIG. 36 is a schematic illustration of a multiple antenna system
3600 implementing a directional antenna subsystem 3602 for satellite downlink
protection.
In an exemplary embodiment, multiple antenna system 3600 represents a wireless
communication system, and directional antenna subsystem 3602 includes a
plurality of
directional antennas 3604 of an AP (also referred to herein as a directional
AP) located
proximate to an operational range of an earth station/satellite subsystem
3606. In some
embodiments, directional antenna subsystem 3602 is implemented as an
alternative to a
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multi-antenna system (e.g., similar to the embodiments described above). In
other
embodiments, directional antenna subsystem 3602 is implemented in a
complementary
manner with a multi-antenna system.
[00443] In exemplary operation of system 3600, each directional
AP/antenna 3604 is configured to provide coverage within a respective coverage
area 3608
substantially disposed in a direction extending away from earth
station/satellite subsystem
3606. In some embodiments, respective coverage areas 3608 may be configured
such that
collectively, coverage areas 3608 are substantially equivalent to a coverage
area provided
by a conventional omni-directional AP (not shown in FIG. 36). However,
irrespective of
similarity of coverage areas, the embodiment illustrated in FIG. 36 realizes
substantial
benefits over a conventional omni-directional AP because, unlike in the case
of the
conventional omni-directional AP, implementation of directional antenna
subsystem 3602
advantageously enables system 3600 to minimize interference from/to earth
station/satellite
subsystem 3606, as described further below with respect to the comparative
examples
depicted in FIGS. 37A-B and described with respect to Table 13.
[00444] FIG. 37A is a schematic illustration of a mobile network 3700
implementing directional coverage implementing directional antenna 3604, FIG.
36, and
FIG. 37B is a schematic illustration of a mobile network 3702 implementing a
conventional
omni-directional antenna 3704. In the exemplary embodiment, directional
antenna 3604
and omni-directional antenna 3704 each represent a respective AP (not
separately
numbered), and may be considered in this example to provide substantially
similar
coverage areas (e.g., coverage areas 3608, 3706, respectively) at
approximately the same
distance to an earth station (ES) 3708, and with respect to a relative
disposition of a
plurality of UEs or FWA transceivers 3710.
[00445] In comparative operation of mobile networks 3700, 3702, the
downlink interference generated by the respective APs 3604, 3704 may be
expected to be
somewhat similar. However, as can be seen from a comparison between FIGS. 37A
and
37B, the uplink power levels from the same distribution of UEs 3710 may be
significantly
different between the two mobile networks. That is, in the case of omni-
directional AP
3704, all of UEs 3710 are contained within coverage area 3706. In contrast, in
the case of
directional AP 3604, at least one of UEs 3710 (e.g., UE 3710(3) in this
example) is outside
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of coverage area 3608, and the relative distribution of UEs 3710 leads to
significantly
different uplink power levels, and therefore also significantly different
potential uplink
interference possibilities, as demonstrated below with respect to Table 13.
TABLE 13
UE-ES
DIRECTIONAL ANTENNA OMNI-D IRE C TIONAL
UE
LOCATION 3710 AN1ENNA 3704
Medium uplink power/ Medium uplink power/
3710(1) UE far from ES
No interference No interference
Low uplink power/ High uplink power/
3710(2) UE close to ES
No interference Potential interference
Outside coverage area/
UE on boresight High uplink power/
3710(3) No communication/
of ES Potential interference
No interference
[00446] According to the exemplary data provided in Table 13, it can be
seen how implementation of directional antennas according to the embodiments
herein may
advantageously substitute for the coverage area of a conventional omni-
directional antenna,
but while obtaining significant advantages over such conventional antennas
with respect to
uplink power and the avoidance of potential interference of UEs.
STOPLIGHT SYSTEM FOR IN-BAND PROTECTION
[00447] As described above, the coexistence of mobile or wireless
communication systems with satellite systems has proven conventionally
difficult to model
with respect to the relatively recent promotion of CBRS in the 3.5 GHz band
spectrum.
Conventional coexistence mechanisms that rely primarily on only priority
tiers, protection
zones, and radio sensing have proven insufficient for the C-band. According to
the
innovative systems and methods described herein though, a network of satellite
beacon
transmitters and detectors (i.e., BRs) enable the generation of a global map
(e.g., within an
individual country, or around the world) of potential radio interference.
According to the
present systems and methods, a dynamic interference map may be created in real
time
using the MBP techniques coordinated by one or more central servers.
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[00448] In an exemplary embodiment of the innovative infrastructures
described herein, individual beacon transmitters may be configured to utilize
the same
transmitters used at small cell base stations, thereby significantly reducing
the need for
installation of additional equipment. In other embodiments, the beacon
transmitters may be
co-located with base stations at the particular FSS sites. Optimally, a
plurality of BRs are
geographically distributed across a wide area, but need not to be of uniform
architecture, as
described above. In some cases, one or more BRs may implement multi-antenna
technologies, such as M11\40, to improve the diversity and sensitivity
capabilities of the
respective receivers. Different BR categories are described below with respect
to FIG. 38.
[00449] FIG. 38 is a schematic illustration of a communication system
3800 In an exemplary embodiment, communication system 3800 is configured to
manage
beacon transmission from a beacon transmitter 3802 to one or more of a variety
of beacon
detector categories distributed in or among a plurality of FSS sites 3804. The
variety of
beacon detector categories include on-site BRs 3806, anchor BRs 3808, and
peripheral BRs
3810 each of which may be configured to directly or indirectly operably
communicate with
one or more servers 3812 (i.e., 1-N servers 3812). According to the exemplary
embodiment
depicted in FIG. 38, the distributed network of beacon transmitter(s) 3802,
detectors/BRs
3806, 3808, 3810, and servers 3812 may be collectively configured (also
referred to herein
as a "stoplight" system) to operate according to the real-time and dynamic
conditions of
system 3800, such that the capability to detect, measure, and mitigate
interference within
system 3800 is significantly improved for more effective satellite system
protection, as well
as more efficient spectrum use.
[00450] In an exemplary embodiment, on-site BRs 3806 include detectors
or receivers that are embedded in, co-located with, and or integral to
respective the satellite
earth stations 3814 of the FSS sites 3804. In some embodiments, the various
receivers of
on-site BRs 3806 are configured to form an array at or approximate to a
respective earth
station 3814 for a more accurate close-field estimate in particular instances.
As described
above with respect to FIG. 15, considering deployment of on-site BRs 3806 in
approximately all 4700 U.S. FFS sites 3804, stoplight system 3800 may be
reasonably
considered to cover approximately 98% of the population utilizing only on-site
BRs 3806.
Nevertheless, it may be desirable to utilize one or more other BR categories
to achieve
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100% coverage, and/or in the case where deployment of on-site BRs 3806 is not,
or cannot
be, achieved.
[00451] Anchor BRs 3808, for example, may include detectors or
receivers deployed near satellite FSS sites 3804 that prohibit or do not
implement on-site
BRs 3806, and/or to extend the effective beacon coverage range beyond 200 dB
in hops.
Peripheral BRs 3810, on the other hand, function to supplement the overall
beacon
infrastructure of stoplight system 3800 through the deployment of additional,
peripheral
detectors/receivers at non-site facilities, such as cable strands, for
example. In some
instances, this deployment of peripheral BRs 3810 advantageously functions
according to
principles similar to those of environmental sensing capability (ESC) for
radar systems.
[00452] In exemplary operation of stoplight system 3800, a local server
(e.g., server 3812(1)) is configured to collect information from one or more
of the
distributed BRs 3806, 3808, 3810, and provides the local view obtained thereby
to a global
server (e.g., server 3812(2) in this example). Alternatively, a plurality of
servers 3812 are
configured to interchange their respective data such that each so-configured
server 3812 is
enabled to build its own global interference map. In the exemplary embodiment,
each such
generated global interference map should be substantially identical to the
global
interference maps generated at other servers 3812. In at least one embodiment
of stoplight
system 3800, N is a substantially large number such that many server providers
3812 are
integrated among system 3800 to more reliably prevent fragmentation or gaps of
coverage.
[00453] In an exemplary embodiment, system 3800 utilizes information
provided to servers 3812 to dynamically generate and/or regenerate a radio map
of
potential interference over the entire area covered by system 3800. Stoplight
system 3800
is therefore further advantageously enabled to establish still further
protection mechanisms,
including without limitation, channel selective transmission, power
restriction, and zoning,
based on the mapping infoimation generated/regenerated by servers 3812.
[00454] Exemplary embodiments of spectrum sharing management
systems and methods are described above in detail, and more particularly,
embodiments
relating to beacon detection system configuration and operation. The systems
and methods
of this disclosure though, are not limited to only the specific embodiments
described
-148-
herein, but rather, the components and/or steps of their implementation may be
utilized
independently and separately from other components and/or steps described
herein.
[00455] Although specific features of various embodiments of the
disclosure may be shown in some drawings and not in others, such illustrative
techniques
are for convenience only. In accordance with the principles of the systems and
methods
described herein, any feature of a drawing may be referenced or used in
combination with
any feature of any other drawing. For example, the following list of examples
represent
only some of the potential combinations of elements possible from the systems
and
methods described herein.
[00456] a(i). A communication system, comprising: an earth station
configured to receive a downlink transmission from a satellite and transmit an
uplink
transmission to the satellite; a server in operable communication with the
earth station; a
beacon detector in operable communication with the server; an access point
configured to
operate within a proximity of the earth station; and a beacon transmitter
disposed within
close proximity to the access point, the beacon transmitter configured to
transmit a beacon
signal to one or more of the server and the beacon detector, wherein the
beacon signal
uniquely identifies the access point, wherein the server is configured to
implement a
measurement-based protection scheme with respect to at least one of the
downlink
transmission and the uplink transmission.
[00457] b(i). The communication system of Example a(i), wherein the
beacon transmitter is integral to the access point.
[00458] c(i). The communication system of Example a(i), wherein the
beacon detector is integral to the earth station.
[00459] d(i). The communication system of Example c(i), wherein the
beacon detector comprises a receiving portion and a transmitting portion.
[00460] e(i). The communication system of Example d(i), wherein the
earth station includes a satellite dish and a frequency agile receiver having
a low noise
block, and wherein the beacon detector receiving portion comprises the low
noise block.
Date Recue/Date Received 2023-04-13
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[00461] f(i). The communication system of Example e(i), wherein the
beacon detector transmitting portion comprises a reporter component configured
to receive
a demodulated beacon signal output from the low noise block and transmit the
received the
demodulated output beacon signal to the server.
[00462] g(i). The communication system of Example e(i), wherein the
server is further configured to dynamically receive site-related information
from the earth
station, including one or more of per-dish frequency usage, direction of
alignment,
elevation, dish size, GPS coordinates, bandwidth usage, antenna azimuth,
elevation angle,
receiving schedule, and noise measurements.
[00463] h(i). The communication system of Example g(i), wherein one or
more of the direction of alignment, the elevation, the antenna azimuth, and
the elevation
angle are dynamically obtained by a measuring device disposed with the earth
station.
[00464] i(i). The communication system of Example a(i), wherein the
beacon detector comprises an external antenna and a transceiver.
[00465] j(i). The communication system of Example a(i), wherein the
server comprises a spectrum access system and a central database.
[00466] k(i). The communication system of Example a(i), wherein the
server comprises a plurality of servers.
[00467] 1(i). The communication system of Example k(i), wherein the
plurality of servers collectively share tasks and communicates in a cloud-
based network.
[00468] m(i). The communication system of Example k(i), wherein a
particular one of the plurality of servers is a master server.
[00469] n(i). The communication system of Example a(i), wherein the
beacon signal includes a received signal strength indication.
[00470] o(i). The communication system of Example a(i), wherein the
beacon detector comprises a distributed receiver.
Date Recue/Date Received 2023-04-13
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[00471] p(i). The communication system of Example a(i), further
comprising a fixed satellite service site.
[00472] q(i). The communication system of Example a(i), wherein the
access point is configured to implement small cell communication.
[00473] r(i). The communication system of Example a(i), further
comprising a plurality of user equipment devices associated with the access
point.
[00474] s(i). The communication system of Example r(i), wherein the
server is further configured to manage the plurality of user equipment devices
using
information included in the beacon signal regarding individual ones of the
plurality of user
equipment devices.
[00475] t(i). The communication system of Example a(i), wherein the
beacon detector comprises a plurality of distributed beacon detectors.
[00476] u(i). The communication system of Example a(i), further
configured to measure interference and utilize portions of the downlink
transmission for
priority access license and general authorized access license sub-bands in the
citizens band
radio service.
[00477] v(i). The communication system of Example a(i), wherein the
downlink transmission includes the 3.7-4.2 GHz frequency spectrum.
[00478] w(i). The communication system of Example a(i), further
configured to measure interference and utilize portions of the uplink
transmission
coordination with existing fixed microwave frequencies.
[00479] x(i). The communication system of Example w(i), wherein the
uplink transmission includes the 5.925-7.125 GHz frequency spectrum.
[00480] y(i). The communication system of Example a(i), further
comprising a first fixed service transceiver and a second fixed service
transceiver.
Date Recue/Date Received 2023-04-13
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[00481] z(i). The communication system of Example y(i), wherein the
first and second fixed service transceivers are configured to operate a point-
to-point
microwave link therebetween.
[00482] aa(i). The communication system of Example y(i), wherein the
server is further configured to implement the measurement-based protection
scheme to
mitigate interference from the earth station into an operation of at least one
of the first and
second fixed service transceivers.
[00483] bb(i). The communication system of Example a(i), wherein the
transmitted beacon signal comprises a 16-bit beacon identifier.
[00484] cc(i). The communication system of Example a(i), wherein the
transmitted beacon signal comprises a 12-bit beacon identifier based at least
in part on
geography.
[00485] dd(i). The communication system of Example r(i), wherein the
plurality of user equipment devices employing small cell unlicensed
transmissions.
[00486] ee(i). The communication system of Example dd(i), wherein the
access point is further configured to report relay information to the server
regarding the
operation of each of the plurality of user equipment devices.
[00487] ff(i). The communication system of Example dd(i), wherein the
access point is further configured to report information to the server
regarding an aggregate
operation of the plurality of user equipment devices.
[00488] gg(i). The communication system of Example ff(i), wherein the
access point is configured to report the information to the server only when
the aggregate
operation of the plurality of user equipment devices exceeds a predetermined
value.
[00489] hh(i). The communication system of Example a(i), wherein the
server is further configured to implement a protection zone layering scheme
about the earth
station.
Date Recue/Date Received 2023-04-13
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[00490] ii(i). The communication system of Example hh(i), wherein the
protection zone layering scheme includes a first area zone about the earth
station and a
second area zone about the first area zone, wherein the second area zone is
larger than the
first area zone.
[00491] jj(i). The communication system of Example ii(i), wherein the
server is further configured to prevent, within the first area zone, the
access point from
using a frequency spectrum utilized by the earth station for the uplink or
downlink
transmissions.
[00492] kk(i). The communication system of Example jj(i), wherein the
server is further configured to authorize, within the second area zone but
outside of the first
area zone, restricted utilization, by the access point, of a portion the
frequency spectrum at
a first power level.
[00493] 11(i). The communication system of Example jj(i), further
comprising a third area zone about the second area zone, wherein the server is
further
configured to authorize, within the third area zone but outside of the second
area zone, the
access point to fully utilize the frequency spectrum at a second power level
greater than the
first power level.
[00494] mm(i). The communication system of Example r(i), wherein one
or more of the plurality of user equipment devices comprises at least one user
equipment
beacon transmitter.
[00495] nn(i). The communication system of Example a(i), wherein the
measurement-based protection scheme is configured to be self-calibrating.
[00496] oo(i). The communication system of Example a(i), wherein the
server is further configured to receive, over a fixed communication path,
information for
at least one distant beacon transmitter operating outside of a proximity in
which the beacon
detector in which the beacon detector is capable of detecting a beacon signal
from the
distant beacon transmitter.
Date Recue/Date Received 2023-04-13
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[00497] pp(i). The communication system of Example a(i), further
comprising a multiple input multiple output (MIMO) antenna in operable
communication
with the earth station.
[00498] qq(i). The communication system of Example pp(i), wherein the
beacon detector comprises the MIMO antenna.
[00499] rr(i). The communication system of Example a(i), wherein the
beacon detector comprises one or more of a platform-mounted beacon receiver, a
station-
integrated beacon receiver, a co-located beacon receiver, and an auxiliary
beacon receiver.
[00500] ss(i). The communication system of Example a(i), further
comprising a distributed antenna system configured to implement the
measurement-based
protection scheme.
[00501] tt(i). The communication system of Example ss(i), wherein the
beacon detector comprises the distributed antenna system.
[00502] uu(i). The communication system of Example ss(i), wherein the
distributed antenna system comprises the beacon detector and a plurality of
remote
antennas.
[00503] vv(i). The communication system of Example a(i), further
comprising at least one of a directional antenna and an omni-directional
antenna.
[00504] ww(i). The communication system of Example a(i), further
comprising a multi-antenna transceiver array.
[00505] xx(i). The communication system of Example ww(i), wherein the
multi-antenna transceiver array is configured to implement at least one of
beamforming
and null forming about the earth station.
[00506] yy(i). The communication system of Example xx(i), wherein the
multi-antenna transceiver array is configured to implement the beamforming and
the null
forming with respect to a mobile user equipment device or a fixed wireless
access
subsystem.
Date Recue/Date Received 2023-04-13
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[00507] zz(i). The communication system of Example a(i), further
comprising a stoplight subsystem including a collective configuration of a
plurality of
beacon transmitters, a plurality of beacon detectors, and a plurality of fixed
satellite service
sites.
[00508] Some embodiments involve the use of one or more electronic or
computing devices. Such devices typically include a processor or controller,
such as a
general purpose central processing unit (CPU), a graphics processing unit
(GPU), a
microcontroller, a reduced instruction set computer (RISC) processor, an
application
specific integrated circuit (ASIC), a programmable logic circuit (PLC), a
field
programmable gate array (FPGA), a digital signal processing (DSP) device,
and/or any
other circuit or processor capable of executing the functions described
herein. The
processes described herein may be encoded as executable instructions embodied
in a
computer readable medium, including, without limitation, a storage device
and/or a
memory device. Such instructions, when executed by a processor, cause the
processor to
perform at least a portion of the methods described herein. The above examples
are
exemplary only, and thus are not intended to limit in any way the definition
and/or meaning
of the term "processor."
[00509] This written description uses examples to disclose the
embodiments, including the best mode, and also to enable any person skilled in
the art to
practice the embodiments, including making and using any devices or systems
and
performing any incorporated methods. The patentable scope of the disclosure
may include
other examples that occur to those skilled in the art.
Date Recue/Date Received 2023-04-13
