Note: Descriptions are shown in the official language in which they were submitted.
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SIMULTANEOUS CHANNEL SWITCHING WITHIN A MESH NETWORK
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present Application claims priority to U.S. Provisional
Patent
Application Number 61/784,795, titled: "System For Minimizing Interference
Through
Simultaneous Channel Switching Within A Mesh Network, And Methods, Devices,
Software,
And Computer-Readable Media Associated Therewith," filed on March 14, 2013, as
well as
U.S. Provisional Patent Application Number 61/951,029, titled: "Simultaneous
Channel
Switching Within a Mesh Network", filed on March 11, 2014.
BACKGROUND
[0002] When deploying a network, a primary concern is often the amount
of
bandwidth available to devices within the home network. This concern extends
to
administrators of commercial, governmental, home, and other types of networks.
For
instance, in a home network, a user may at times receive multiple streams of
video. As high
definition video is increasingly available, the user or administrator of the
network may want
to ensure that the technology used within the home network is sufficient to
support the data
requirements of multiple streams of high definition video.
[0003] Although applicable to all networks, users deploying home
networks may
also be very cognizant of the cost of deployment. There may therefore be a
balance to obtain
sufficiently capable technology at the lowest cost. In making that
determination, a home
network user may select any of several wired technologies to deliver
compressed video. For
instance, MOCA, HPNA, and PLC may be available. In other embodiments, however,
user
may opt to use a wireless network. Some wireless networks may expand the
coverage area,
allow connecting devices to be more portable, and may even be deployable at
less of a cost.
WiFi (i. e. , 802.11 wireless) is often used as a wireless technology capable
of provided desired
coverage at an economical cost.
[0004] WiFi, and particularly 802.11n wireless, may be used to reach
virtually
any corner of a building, and to connect to a wide variety of devices. Example
devices that
may use WiFi connectivity include desktop and laptop computers, tablet
computing devices,
televisions, residential gateways, set-top boxes, game consoles, voice over IP
phones, smart
phones, and other devices. WiFi is, however, at times unpredictable and
unreliable due to the
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nature of wireless signal propagation and the pervasiveness of interference in
the unlicensed
spectral bands where WiFi operates.
DISCLOSURE OF THE INVENTION
[0005]
According to at least one embodiment, a computer-implemented method
for channel switching in a mesh network is described. In one embodiment, a
beacon may be
sent. The beacon may include a channel change request in both proprietary and
standard
formats. The channel change request may include an instruction to change to a
particular
channel and a timing synchronization function identifying when the change to
the particular
channel should occur. The timing synchronization function may be used to
determine that
the time has arrived to change to the particular channel. The particular
channel may be
changed to synchronously with all other access points in a mesh network.
[0006] In one
embodiment, the timing synchronization function may include
information for identifying one or more of the following: a time prior to the
time for changing
to the particular channel when a transmission queue should be stopped, a time
prior to the
time for changing to the particular channel when a reception queue should be
stopped, a time
after the time for changing to the particular channel when the transmission
queue should be
restarted, and a time after the time for changing to the particular channel
when the reception
queue should be restarted.
[0007] In some
embodiments, prior to sending the beacon, a prior beacon may be
received. Sending the beacon may be performed by an access point after receipt
of a prior
beacon that includes the channel change request. Information from the prior
beacon may be
added into the sent beacon. In some cases, adding information from the prior
beacon may
include changing the timing synchronization function to account for time
differences as a
result of at least time to receive and send beacons. In some cases, the change
to a particular
channel may be registered using a callback function. In some embodiments, one
or more
operations described herein may be performed by an access point. The access
point may
include a kernel mode having a proprietary kernel module. In some cases, the
standard
format may include an implementation in an action frame of 802.11 channel-
switch
announcement (CSA) elements to allow channel changes by devices that do not
have access
to the proprietary format.
[0008] In one
embodiment, prior to sending the beacon, a clear channel
assessment request identifying a particular channel for a clear channel
assessment may be
sent. The clear channel assessment may include information for identifying two
or more of
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identification of a primary channel for the clear channel assessment,
identification of a
secondary channel for the clear channel assessment, a sampling duration, a
sampling period,
and a time synchronization function on when to perform the clear channel
assessment. In
some cases, sending the clear channel assessment request may include adding
information
from the prior clear channel assessment request. The clear channel assessment
may be
performed, on all channels, synchronously with other access points in the mesh
network.
Performing the clear channel assessment may include determining if power on a
sampled
channel is above or below a power threshold. Performing the clear channel
assessment may
include measuring how busy the channel is. The busyness of a channel may be
inversely
proportional to a bit asserted for each sample where power is below a
predetermined
threshold.
[0009] A
computing device configured to obscure content on a screen is also
described. The device may include a processor and memory in electronic
communication
with the processor. The memory may store instructions that may be executable
by the
processor to send a beacon, the beacon including a channel change request in
both proprietary
and standard formats. The change channel change request may include an
instruction to
change to a particular channel and a timing synchronization function
identifying when the
change to the particular channel should occur. The memory may store
instructions that may
be executable by the processor to use the timing synchronization function,
determining that
the time has arrived to change to the particular channel and change to the
particular channel
synchronously with all other access points in a mesh network.
[0010] A
computer-program product to obscure content on a screen is also
described. The computer-program product may include a non-transitory computer-
readable
medium that stores instructions. The instructions may be executable by the
processor to send
a beacon, the beacon including a channel change request in both proprietary
and standard
formats. The change channel change request may include an instruction to
change to a
particular channel and a timing synchronization function identifying when the
change to the
particular channel should occur. The memory may store instructions that may be
executable
by the processor to use the timing synchronization function, determining that
the time has
arrived to change to the particular channel and change to the particular
channel
synchronously with all other access points in a mesh network.
[0011] Features
from any of the above-mentioned embodiments may be used in
combination with one another in accordance with the general principles
described herein.
These and other embodiments, features, and advantages will be more fully
understood upon
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reading the following detailed description in conjunction with the
accompanying drawings
and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The
accompanying drawings illustrate a number of exemplary
embodiments and are a part of the specification. Together with the following
description,
these drawings demonstrate and explain various principles of the instant
disclosure.
[0013] FIG. 1
schematically illustrates an example mesh network according to
one embodiment of the present disclosure;
[0014] FIG. 2
schematically illustrates example data paths of two signals within
the mesh network of FIG. 1, according to one embodiment of the present
disclosure;
[0015] FIG. 3A
illustrates a building having multiple wireless devices for
receiving data transmitted within a communication network, and additional
wireless devices
which may provide interference, according to one embodiment of the present
disclosure;
[0016] FIG. 3B
illustrates the building of FIG. 3A, and shows example wireless
devices with antennas for receiving communications within a mesh network,
according to one
embodiment of the present disclosure;
[0017] FIG. 4A
schematically illustrates an example communication system in
which two devices with four antennas may maintain four independent data
streams, according
to one embodiment of the present disclosure;
[0018] FIG. 4B
schematically illustrates the example communication system of
FIG. 4A, in which the antennas of the devices may use beamforming to combine
data
streams, according to one embodiment of the present disclosure;
[0019] FIG. 5
graphically illustrates a comparison of throughput for a 4x4 MIMO
system with beamforming relative to two different 3x3 MIMO systems, according
to one
embodiment of the present disclosure;
[0020] FIG. 6
illustrates an example access point including user and kernel
modes, the kernel mode including a proprietary kernel module for communicating
channel
change and clear channel assessment messages, according to one embodiment t of
the present
disclosure;
[0021] FIG. 7
illustrates an example method for performing a channel switch
according to some embodiments of the present disclosure;
[0001] FIG. 8
is a flow diagram illustrating one embodiment of a method for
simultaneous channel switching in a mesh network; and
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[0022] FIG. 9
illustrates another example method for performing a channel switch
according to some embodiments of the present disclosure, the method of FIG. 9
further being
generally applicable to a manner in which a clear channel assessment and radar
detection may
be performed in other embodiments of the present disclosure.
[0023] While
the embodiments described herein are susceptible to various
modifications and alternative forms, specific embodiments have been shown by
way of
example in the drawings and will be described in detail herein. However, the
exemplary
embodiments described herein are not intended to be limited to the particular
forms disclosed.
Rather, the instant disclosure covers all modifications, equivalents, and
alternatives falling
within the scope of the appended claims.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
[0024] Systems,
methods, devices, software and computer-readable media
according to the present disclosure may be configured for use in a wireless
communication
system. More particularly, systems, methods, devices, software and computer-
readable
media may be used to maintain reliable communications over extended ranges,
and with
channel interference resiliency. Without limiting the scope of the present
disclosure, some
embodiments may specifically relate to providing synchronous and collective
changes to
communication channels, without disassociation, and in a manner that may
reduce dropped
packets and interference. In at least some embodiments, availability of other
communication
channels may be assessed by multiple wireless access points and/or stations in
a synchronous
manner.
[0025]
Embodiments of the present disclosure relate generally to wireless
communication systems. More particularly, embodiments of the present
disclosure relate to
systems, methods and devices for mitigating interference and maintaining
connectivity within
a wireless communication system. More particularly still, embodiments of the
present
disclosure relate to systems, methods, devices, computer-readable media, and
software for
resiliently and dynamically adjusting to channel interference to maintain
reliability and
extend range within a wireless network.
[0026] In
accordance with some embodiments of the present disclosure,
interference is mitigated or avoided by changing the communication channel at
each access
point, node, or station within a wireless mesh network. Each channel can
change the channel
simultaneously so as to minimize or eliminate dropped data packets while
maintaining an
association between access points and stations.
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[0027] To
change channel synchronously, an initiating access point may
determine a channel change is desired using clear channel assessment or other
measures. A
message may be prepared and sent as a beacon, which message can identify the
channel to
change to, and the time at which the change should occur. A receiving access
point may set a
timer to make the change at the specified time. The receiving access point may
also add the
channel change information to an outgoing beacon to allow the message to
propagate through
the full mesh network prior to the time to change channel occurs.
[0028] In
accordance with at least some embodiments of the present disclosure, a
channel change procedure is based on a clear channel assessment. The clear
channel
assessment may also be performed by requesting all access points and/or
stations within the
mesh network perform the clear channel assessment on the same channel or
channels, at the
same time. Each access point may register its results and report the results.
An initiating
access point may interpret the results and use the results to initiate a
channel change
simultaneously at all nodes of the mesh network.
System Overview
[0029] To
better understand aspects of the present disclosure, FIG. 1 illustrates an
example wireless networking system 100 that may be used in connection with
some
embodiments of the present disclosure. It should be appreciated that the
wireless networking
system 100 is merely one example of a suitable system for use with embodiments
of the
present disclosure, and should not therefore limit embodiments described
herein to any
particular structure.
[0030] The
wireless networking system 100 of FIG. 1 illustrates an example mesh
network that may use multiple nodes, or access points 102a-g, that can
collectively route
information to any of multiple stations 104a-e or devices. The particular
system 100 of FIG.
1 may be dynamic and adaptive to respond to conditions within the network,
including
interference from any of a variety of sources.
[0031] In this
particular embodiment, the system 100 may include a service
provider 101 which provides network communication services. Although not
necessary, an
example of a service provider 101 may include an Internet service provider
("ISP"). In such
an embodiment, some components of the system 100 may collectively form a local
area
network (e.g., components 102-108), or other type of network to access data
available
through the service provider 101 and/or to send information to the service
provider 101.
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[0032] In FIG.
1, the local area network, or other network, may include a
distribution switch 106 which communicates with the service provider 101. The
distribution
switch 106 may communicate with an access switch 108. The distribution switch
106 and
access switch 108 may be connected to allow the transfer of communication. The
access
switch 108 may also connect to one or more access points 102a-g. As noted
above, the
access points 102a-g may be examples of nodes that can form a mesh network.
Through a
mesh network, the access points 102a-g may communicate with each other to
transfer
communications and messages within the network. In some embodiments, any
access point
102a-g may be able to communicate with any other access point 102a-g. The
access points
102a-g may use wireless communication to communicate. Thus, if two access
points 102a-g
are unable to communicate, it may be due to factors such as distance or
interference (e.g.,
physical objects obstructing communication), and not necessarily
incompatibility.
[0033] Any of a
number of electronic devices 104a-e may attempt to
communicate with the service provider 101. For instance, a computing device
(e.g., laptop
computing device 104b, 104c) may communicate with the service provider 101.
Alternatively, a portable electronic device (e.g., smart phone 104a, 104d) may
communicate
with the service provider 101. In other embodiments, other devices (e.g., set-
top box 104e)
may communicate with the service provider 101. Where the access points 102a-g
are
wireless access points, any or all of the devices 104a-e may be capable of
communicating
wirelessly with an access point 102a-g. FIG. 1 illustrates, in dashed lines,
potential
communication links within the system 101, both between access points 102a-g
themselves,
between access points 102a-g and devices 104a-e, and between access points
102a-g and the
access switch 108.
[0034] As
discussed herein, the system 100 may be dynamic and adaptive in order
to allow communications between devices 104a-e and the service provider 101.
An adaptive
system may route communications in different manners depending on which device
104a-e is
used and/or based on other conditions in the system 100. FIG. 2 illustrates
some example
manners in which the system 100 of FIG. 1 may be used to pass a set of
communications.
[0035] In
particular, FIG. 2 illustrates two example signals 110a, 110b that may
be passed using the system 100 of FIG. 1. A first signal 110a allows the
service provider 101
to communicate with a particular device, which in this case may be the laptop
computing
device 104c. The second signal 110b may also allow communication with the
service
provider 101, but this example uses communication with the portable electronic
device 104a.
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The routing of the signals 110a, 110b may be different, and may even change,
based on
conditions within the system, including the locations of the devices 104a,
104c.
[0036] A signal
intended for a device 104c may be received by the distribution
switch 106, and passed to the access switch 108. At that point the access
switch 108 may
determine which of the nodes 104a-g may be used to pass the information to the
device 104c.
In this particular embodiment (as shown in FIG. 1), the device 104c may be in
communication with a particular node (e.g., access point 1020.
Consequently,
communication may be routed from the access switch 108, through the access
points, until
reaching the access point 102f. The access point 102f may then transfer the
signal to the
device 104c.
[0037] FIG. 2
illustrates a particular path the signal 110a may follow. More
particularly, FIG. 2 illustrates that the signal may be passed by the access
switch 108 to an
access point 102a, which can then send the signal to an additional access
point 102f. In this
case, the access point 102f may be associated with the device 104c, so the
device 104c may
then receive the signal from the access point 102f. Optionally, a response
signal may be sent
back to the service provider 101. In this particular embodiment, the signal
110a includes a
response which follows the same path back to the service provider 101.
Specifically, the
signal may be passed from the device 104c to the access point 102f. The access
point 102f
can communicate the signal to the access point 102a, which in turn
communicates the signal
to the access switch 108. The access point 108 communicates with the
distribution switch
106, which can communicate with the service provider 101 (see FIG. 1).
[0038] The
second signal 110b may allow communication with a different device
104a, which can potentially be in a different location. Consequently, the
communication path
used by signal 110b can optionally be different. In particular, the device
104a is shown in
FIG. 1 as being associated with an access point 102c, so communication of the
signal 110b
may pass through the access point 102c.
[0039]
Transmission of a signal 110b to the device 104a may start similar to
signal 110a, and may pass from the distribution switch 106 to the access
switch 108.
Thereafter, however, the path may diverge. In this particular embodiment, the
signal 110b
may then be passed, in order, through access point 102b, access point 102g,
access point
102d, and access point 102c before being routed to the device 104a. A return
path of the
signal 110b to the service provider could follow a similar path. In FIG. 2,
however, the
return path may be different. For instance, an access point may disassociate
with the system
100, may be affected by interference, or otherwise be affected. Consequently,
a different
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return path may be dynamically determined. In particular, FIG. 2 illustrates a
return path
from the device 104a as going through the access point 102c, and access point
102b before
being directed to the access switch 108 and distribution switch 106.
[0040] The
example system 100 of FIGS. 1 and 2 may be used in a variety of
different environments. For instance, in at least some embodiments the system
100 may
include a network suitable for use in a single building (e.g., home, office,
etc.). The use of
multiple access points 102a-g may allow signals to be re-routed along any of
multiple paths
to reach a destination. In other embodiments, however, the system 100 may be
suitable for
use in larger or smaller locations. In an example of a larger system, the
service provider may
provide broadband or other Internet access to a neighborhood or geographical
region wider
than a single building. Multiple access points 104a-g may be dispersed
throughout the
geographical region in order to provide Internet access to multiple devices at
any of multiple
homes, buildings, or other locations. In at least some embodiments, the system
100 may
therefore be widely distributed, although such distribution is not required
for all embodiments
of the present disclosure.
[0041] In order
to allow communication between the various access points 102a-g
and devices 104a-e of the system 100, each component in a communication path
may
generally create an association, or communication link, to allow wireless
communication to
occur. The communication may follow particular protocols and, in at least some
embodiments, may use a particular channel or frequency for communication. Each
of the
components 102, 104 may use the same frequency or channel in order to pass
communications.
[0042] An
example protocol or technology that may be used to pass wireless
communications includes WiFi (e.g., 802.11) signals. One aspect of WiFi
signals, and
virtually all wireless signals, is that they may often be affected by
interference. Due to
interference, the data rate and reliability of WiFi signals may increase or
decrease. In
general, as signal power increases, data rate and reliability increase, while
decreasing with
reduced signal power. Interference reduces the signal power.
[0043]
Interference that degrades signal quality, and thus data rate and reliability,
may come from any number of sources. For instance, signal power may fall off
inversely
with the distance between wireless components. Thus, a receiver that is
located far from a
transmitter may receive less signal power as compared to a nearer receiver.
With less power,
a receiver may not be able to support as high of data rates as a closer-range
receiver.
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[0044]
Interference may also come from other sources. Physical objects may, for
instance, impede the direct path, or line of sight, of a signal. Signals may
be reflected, which
can result in a multipath. Reflection of signals can reduce power and re-
direct signals,
leading to reduced power and dead spots within a network.
[0045] Even in
the absence of reflection, a wall or other physical objects may also
decrease power of a signal. The amount of power loss, or attenuation, may vary
based on the
type of material. For instance, a home with concrete walls may cause, in some
cases, up to
50 dB loss. With such power loss, it may be difficult to maintain a
communication link or
association between wireless components. In contrast, homes with thinner walls
(e.g., wall in
homes in Japan), may experience far less signal attenuation.
[0046] Other
wireless devices may, however, also provide interference. If another
device produces a wireless signal in the same or a nearby frequency band, the
signals can
saturate a receiver and cause excessive noise, thereby degrading performance.
The above
example of a home with thin walls, for instance, may benefit from less
attenuation due to wall
thickness, but may also allow more signals from nearby locations to be
received at a receiver.
Examples of devices that may cause interference in a WiFi setting can include
other WiFi
networks, microwaves, cordless phones, Bluetooth devices, wireless video
cameras, wireless
game controllers, fluorescent lights, WiMAX, Zigbee devices, and other
devices, or any
combination of the foregoing.
[0047] FIG. 3A
illustrates an example building 200 in which wireless signals may
be transmitted, and in which interference may occur. In particular, the
building 200 may
include various devices 204a-g which can operate using, or put off, a wireless
signal. For
instance, the illustrated building 200 includes two televisions 204a, 204b,
either of which
may receive wireless signals over a communication network (e.g., the mesh
network 100 of
FIG. 1). In this particular embodiment, the television 204a may also be
connected to a set-
top box 204c or other similar device, which may also receive wireless signals.
A computing
device 204d in another room may similar connect to the wireless network (e.g.,
to an access
point of the wireless network) to communicate with a service provider or other
devices within
the system. Other wireless devices in the building 200 include a cordless
phone 204e, a
mobile phone 204f, and a gaming system 204g having wireless controllers.
[0048] In the
particular embodiment in FIG. 3A, the wireless signals received by
some wireless devices (e.g., 204a-d) may be affected by signals of other
devices (e.g., 204e-
g), which can potentially operate using a different network or system. Due to
interference,
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packets of information sent along a WiFi or other network may be lost, or
associations
between devices and access points may even be lost.
[0049]
Maintaining a suitable data rate may be increasingly significant as there is
a continually rising use of bandwidth. Data rate is dependent on time (i.e.,
how much data is
used over a period of time), and can be particularly affected by large data
sets, such as
increasingly higher resolution video. This trend can be associated with
increased use of flat
panel displays of larger size, higher resolution (e.g., 1080i-30 to 1080P-60),
higher contrast
ratio, higher color resolution, increased dynamic range for high definition
content, higher
frame rates (e.g., 120/240 frames per second), availability of three-
dimensional
programming, and the like, or any combination of the foregoing. Although
compression
(e.g., H.264 compression) allow data to be compressed, high definition video
may still use a
lot of bandwidth. For instance, high resolution video may still use 30 Mbps or
more, as
compared to the 8-12 Mbps used by video data of the past.
[0050]
Embodiments of the present disclosure may allow wireless transmission of
large quantities of data, including, but not limited to, high definition video
data. Such data
can be transmitted in accordance with embodiments disclosed herein by
maintaining high
reliability and data rates, while also minimizing packet loss, dead spots, and
disassociation
among wireless access points and devices.
[0051] To
appreciate some of the manners in which embodiments of the present
disclosure may be used, a description of various concepts of the present
disclosure will be
described in greater detail. Each of these concepts may be used alone, or in
combination, in
some embodiments of the present disclosure. Thus, while described individually
in some
cases, it should be appreciated that any concept or feature described herein
may be used in
connection with any other feature or concept. Example features described
include:
= Mesh networking;
= Multiple-input multiple-output (MIM0);
= Dynamic Digital Beamforming;
= Receiver processing;
= Fast Channel Switching;
= Clear Channel Assessments; and
= Channel Scanning.
Each of the foregoing is described in greater detail herein.
Mesh Networking
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[0052] Mesh networking generally includes the use of multiple access
points, or
nodes, to facilitate communication between different devices or systems. The
system 100 of
FIGS. 1 and 2 is one example of a mesh network. Mesh networking provides
scalability, and
may be used with both small and large locations. Thus, a small home may
utilize mesh
network, as may a larger home, an office building, or even larger locations,
all while
obtaining nearly 100% wireless coverage.
[0053] Mesh networking may also provide dynamic communication. As
discussed herein, particularly with respect to FIG. 2, communications may be
routed and re-
routed based on a variety of conditions. For instance, a receiving device at
one location may
associate with a particular access point, and communications may pass along
one path of
different access points to enable communication with another device or a
service provider. If
the device moves, if a connection degrades, or if another condition occurs,
the mesh network
may dynamically re-route end-to-end communications to provide suitable
reliability and data
rates. In some embodiments, each access point may also operate at least
partially
independently. A mesh network may not use a controller, and may instead allow
each access
point to use point-to-point or point-to-multipoint communications to pass
signals.
MIMO
[0054] MIMO refers to the use of multiple inputs and multiple outputs in
the
context of a radio channel carrying a signal. For a MIMO system, various
devices may
include multiple antennas that are used to transfer signals between
transmitters and receivers.
Each access point, end-user device, or other components in the system may act
as both a
transmitter and/or receiver in certain embodiments. MIMO may provide the
ability to
increase data rates, range, and reliability, all while not utilizing
additional bandwidth or
substantially, if at all, increasing transmission power.
[0055] To use MIMO, the multiple antennas may use channels
independently, so
as to send multiple data streams. FIG. 3B, for instance, illustrates the
building 200 of FIG.
3A, but illustrates various devices as including multiple antennas 212. In
this particular
embodiment, the television 204b, set-top box 204c, computing device 204d, and
gaming
system 204g may each have multiple antennas 212 for use in connection with a
MIMO
system.
[0056] In general, the number of antennas 212 used may be configurable,
and can
change according to system requirements, cost concerns, or the like. Each
antenna may,
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however, support an independent data stream, and more antennas may thus
increase the
number of independent data streams available. A 2x2 MIMO system may include
two
antennas at the transmitter and two antennas at the receiver, and can support
two independent
data streams. Similarly, a 3x3 MIMO system may support up to three independent
data
streams, and a 4x4 MIMO system can support four independent data streams.
Dynamic Digital Beamforming
[0057] Dynamic digital beamforming ("DDB") may relate to the use of
antennas
to focus energy between devices on a per-packet basis. More particularly, DDB
may take
advantage of directional or spatial knowledge in order to focus radio in a
particular direction.
A signal may be sent, for instance, by each of two antennas. Where the signals
overlap,
signals may be amplified. Steering signals, delaying signals from one antenna,
and the like
may therefore direct the amplification to a particular location and/or
distance. FIG. 4A
schematically illustrates an example 4x4 MIMO system 300 which can send
independent
streams, and FIG. 4B illustrates the same 4x4 MIMO system 300 with DDB used to
effectively combine streams and provide enhanced reliability.
[0058] DDB may be used in connection with MIMO to obtain some additional
gains in reliability and/or data rate. In a 2x2 MIMO system, for instance, two
data streams
may be provided; however, with no additional antennas there may be marginal
benefits to the
two data streams. In contrast, a 3x3 MIMO system may also support two data
streams, but
can include an additional antenna. That additional antenna may allow more
beamforming to
take place, thereby providing added reliability. Further improvement can be
seen in a 4x4
MIMO system that includes two additional antennas beyond those used for two
data streams.
In a 4x4 MIMO system, the two additional antennas allow focusing of energy in
two
directions, and some embodiments can provide gains of 12-25 dB, or more,
relative to signals
sent without beamforming.
[0059] In general, the more antennas that are provided, the more
antennas can be
used for providing independent data streams and/or for beamforming. Additional
antennas
may thus provide additional spatial dimensions to be combined and to provide
greater
reliability.
[0060] While additional antennas may be used, it may not be necessary,
or even
desirable, to continually increase the number of antennas. For instance, if a
single data
stream is provided, two antennas may provide nearly 100% reliable use.
Similarly, if two
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data streams are to be supported, four antennas may provide nearly 100%
reliable use. Table
1, below, summarizes the reliability of various systems that include both MIMO
and DDB.
2 3x3 4x
Configuration
x2 4
% of channels supporting 9 100 10
1 max-rate data stream 9.5% % 0%
% of channels supporting 4. 68. 99
2 max-rate data streams 4% 1% %
Table 1
[0061] DDB can be used by applying weight factors to each antenna, to
thereby
steer energy in an independent spatial direction associated with the data
stream, while
avoiding interference. Channel estimation can be used, and may be explicit or
implicit. For
instance, explicit feedback of the weights and channel estimates may be
received from a
receiver. In other embodiments, metrics such as minimizing packet error rate
may be used to
obtain implicit feedback on the weight factors being applied. DDB may also
provide
enhanced flexibility as the weight factors can be changed based on the
feedback. In contrast
to switched beamforming, which limits switching between fixed antenna patterns
pointing in
a single spatial direction, weight factors can be varied in any desired
manner.
Receiver Processing
[0062] Receiver processing may be used in connection with MIMO and/or
DDB
to further provide improved throughput, range, and/or reliability of a
wireless signal. In some
embodiments, the antennas may be optimally adapted to the characteristics of
MIMO channel
frequency response, the number of data streams, and the receiver positions.
For instance, in a
4x4 MIMO system, two extra antennas (assuming 2 independent data streams are
supported),
may focus energy in two directions to reduce interference and move the signal
away from
other locations.
[0063] In particular, while DDB may use additional antennas to steer
transmitted
data in a particular spatial direction, receiver processing may apply weight
factors to antenna
inputs to steer an array pattern in the direction of detecting and receiving
an incoming data
stream. Combining receiver processing and DDB may therefore collectively steer
and
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receive data streams in an optimal manner to produce increased throughput,
reliability, and
range.
[0064] Another aspect of receiver processing may be the ability to
counteract
interference. When weight factors are applied, weighting may place nulls in
the directions of
interference sources. Thus, a 4x4 MIMO system providing two extra antennas can
potentially null-out two interference sources. Nulling an interference source
may, however,
change the ability to steer an array in the direction of an incoming data
stream. For instance,
if one antenna is used to null an interference stream, it may be unable to
also steer an array
toward an incoming data stream, leaving only one antenna to do so. Receiver
processing can
thus optimize performance by combining nulling out interference and maximizing
received
signal power by steering an array toward incoming data streams. In some
embodiments,
receiver processing may suppress interference effects so that transmitted
signals in the spatial
direction are orthogonal to that of interference sources.
[0065] Combining MIMO, DDB, and receiver processing can provide
significant
gains over systems lacking any or all of such components. FIG. 5, for
instance, illustrates an
example graph representing the average throughput of various systems. The
graph illustrates
throughput as it relates to distance or range. A first condition 402
represents a 4x4 MIMO
system with adaptive processing in transmit and receive antenna arrays (i.e.,
using DDB and
receiver processing), and shows significant gains relative to 3x3 MIMO systems
with
switched beamforming (condition 404) and without any beamforming (condition
406).
Fast Channel Switching
[0066] As discussed herein, embodiments of the present disclosure may
include
use of a wireless communication system in which multiple nodes and/or devices
associate
over wireless communication links. The communication links may then be used to
transfer
information within the network. Optionally, the network includes components
discussed
above, including mesh networking to reach difficult to reach locations using
mesh elements
between transmitters and receivers. Other features may include MIMO (e.g., 4x4
MIMO)
that enables DDB with explicit or implicit channel estimates to obtain
multiple data streams
at high channel level gain and low interference over longer distances, with
maximized gain in
the direction of the incoming data streams. Receiver processing may also be
used to null out
interference sources, to steer an array toward an incoming signal, or some
combination
thereof
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[0067] When communicating wirelessly, the various components may
communicate over a particular channel or frequency within a frequency band. In
a wireless
chipset, the radio channel that is used may become congested or over-
subscribed. In a mesh
network, mesh points may begin to lose connection to an access point. Those
who lose a
connection may be considered to be on the so-called "cell edge," and can
become
inaccessible. In an example home security setting, a video surveillance camera
at a cell edge
may become disassociated with an access point, which can cause a loss of
signal, making it
impossible to monitor the video.
[0068] Certain aspects of the present disclosure may relate to changing
channels
to maintain reliability, data rates, and range. A channel change may be
performed in
response to detecting interference (e.g., explicitly or implicitly), although
a channel may be
changed for any number of reasons as well.
[0069] According to some embodiments of the present disclosure, a single
radio
channel can be shared among multiple mesh peers, and potentially among other
end-user or
other devices, which can be considered "stations". Each mesh peer, or access
point, may
have user and kernel modes where certain actions can be initiated, registered,
or otherwise
processed. FIG. 6 illustrates an example of one type of a system that may be
used, and
which includes both kernel and user modes. As illustrated, a proprietary
kernel module is
included in the kernel mode. The kernel module may be used, in some
embodiments, in a
communication path between a link state router (e.g., in the user mode) and an
802.11
module.
[0070] According to some embodiments of the present disclosure, the
kernel
module may be used to apply a channel change as a countermeasure (e.g., when a
signal
degrades) or take other actions (e.g., to test the state of a mesh or
communication link, test
availability of other channels, etc.). One mechanism that may be used by the
kernel module
may be to utilize open shortest path first ("OSPF") protocols, and to set
Hello protocol
timers. Optionally, IGMP snooping may be disabled in the kernel module to
facilitate flow
of protocol timers, which can act as a primary trigger to make hidden nodes
visible. The
kernel module may provider simpler, specific, and stable interfaces at all
access points or
other nodes in order to facilitate such actions. Collectively, such features
provide flexibility
to recover and regain original communication links.
[0071] The kernel module may be used in some embodiments to change
channels
in a manner that allows access points and other stations to maintain
associations with
potentially no lost packets. This may be done by allowing all access points to
switch to the
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same channel, in sync with a parent access point, which may be a peer access
point who
determines that the channel switch is desirable. Requests to change channel
can be made and
propagated throughout the mesh network so that the entire mesh network can
change
channels instantaneously and synchronously, thereby minimizing or avoiding
disruption to
stations and access points.
[0072] Turning now to FIG. 7, an example method 700 is provided for
performing a channel switch according to some embodiments of the present
disclosure. The
illustrated embodiment represents, merely one example of a manner in which all
access
points and associated stations (i.e., connected devices) may switch channels
in a WiFi or
other wireless system, although other methods may be used. For instance, the
illustrated
method 700 illustrates a message that may propagate through three components
(e.g., two
access points and a station, three access points, etc.), although in other
embodiments the
method may include message propagation through any number of components, or
through
only two components.
[0073] The method of FIG. 7 includes a first access point sending an
outgoing
message in act 702. The outgoing message may include a beacon or other message
prepared
by, or using, an example kernel module, and can facilitate changing of
channels
simultaneously. For instance, the outgoing message may provide data for a
channel switch,
including what channel to switch to, and a timing synchronization function
("TSF"). The
TSF may include a measure of time on a given device to allow all devices to
change channels
at the same time. The TSF may be an absolute value, or a relative value.
Further, the TSF
may correspond to a time sufficiently far in the future to allow messages to
propagate to all
access points and stations, thereby allowing all devices in the communication
system to
switch channels simultaneously.
[0074] A second access point may listen for a beacon or other message,
and in act
704 may receive the message. In some embodiments the message sent in act 702
may be
directed to the second access point in a point-to-point communication. In
other
embodiments, however, the message in act 702 may be sent in other manners,
including as a
broadcast or point-to-multipoint message. Regardless of how the message is
sent in act 702,
it may be recited in act 704.
[0075] The second access point may be associated with other access
points or
stations. As a result, the second access point may prepare and send beacons or
other
messages to associated devices. Upon receipt of the message in act 704,
however, the second
access point may add information from the received beacon to its own messages,
and send the
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revised beacon or other message in act 706. A third access point, a station,
or other device
may then receive the beacon or other message in an additional act 704. If the
third device is
an access point, the access point may also add the received channel change
information (e.g.,
channel and TSF) to its own messages and send the message in act 706 with the
revised
information. If the third device is a station, such as an end-user device, the
act 706 may be
omitted.
[0076] When the time associated with the TSF arrives, each of the
devices may
change the channel (acts 708). Thereafter, each device may register the change
(acts 710).
Registering the change may include each device, or each access point, calling
a callback
registered by the proprietary kernel module. Optionally, each device making
the change can
report back in acts 712 to another device to indicate that the channel change
was made. The
reports may ultimately be funneled back to the first device which initiated
the change, and
which can receive the reports in act 714.
[0077] Various elements of the method 700 may be performed in a variety
of
manners. For instance, the manner in which the channel change information is
provided can
be varied. In one embodiment, for instance, the kernel module includes
proprietary structure
for sending, receiving, or implementing channel changes, and the message sent
can conform
to such a structure. In other embodiments, a message may conform to a
standard. For
instance, a message may be implemented in an action frame of 802.11h channel-
switch
announcement (CSA) elements to allow channel changes by devices that do not
have access
to proprietary systems. In some embodiments, both standardized (e.g., CSA
elements and
action frames) may be used in addition to proprietary structures and methods.
Sending both
types of messages may allow devices that understand only standard messages,
and devices
that understand proprietary messages, to both respond and change channel
synchronously. In
other embodiments, however, devices receiving and interpreting only the CSA or
other
standard message may have some loss of timing accuracy. For instance, a CSA
element may
have accuracy limits based on timing accuracy limits of beacon levels in
802.11h.
[0078] The TSF function may also be the same or different for each of
the access
points or other devices in the method 700. If, for instance, the TSF refers to
an absolute time,
the TSF may remain constant as a message propagates through a network. A
relative TSF
may, however, be adjusted at each hop. For instance, after receiving the
message in act 704,
the second access point may add the TSF and channel change information in act
706, but may
first adjust the TSF information. The TSF information may be adjusted by, for
instance,
calculating a new TSF based on the difference between time at the second
access point and at
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the initiating, or first, access point. The adjustment may reflect the time
difference resulting
from the delay in receiving the message in act 704, and adding and sending the
message in
act 706.
[0079] While the registration in acts 710 is shown as occurring
following a
change in channel (acts 208) responsive to a message including channel change
information
from an initiating access point, the registration in acts 710 may also be
performed at any
suitable time. For instance, registration may be performed using a callback
function
regardless of why the channel changed. Thus, if the channel change was
initiated locally at
an access point, due to a message from a peer, due to a radar event, through a
local user
interface, or in some other manner, the callback may be initiated to register
the channel
change. Registration may include updating an index to indicate what channel is
currently
being used. The channel index may also be used to identify what channel to
switch to in acts
708.
[0080] The method 700 of FIG. 7 includes sending of a message in act 702
by a
first access point initiating a change in all access points and stations.
Although a single
access point may initiate the change, it should be appreciated that the
initiating access point
may be any access point in a system. Thus, any access point that determines a
channel
change should occur may act as the first access point and transmit channel
change
information in a corresponding beacon or other message.
[0081] Turning now to FIG. 8, a flow diagram illustrating one embodiment
of a
method 800 for simultaneous channel switching in a mesh network is
illustrated. In some
configurations, the method 800 may be implemented in conjunction with one or
more devices
from the wireless networking system 100 of FIG. 1.
[0082] At block 805, a beacon may be sent. The beacon may include a
channel
change request in both proprietary and standard formats. The channel change
request may
include an instruction to change to a particular channel and a timing
synchronization function
identifying when the change to the particular channel should occur. At block
810, the timing
synchronization function may be used to determine that the time has arrived to
change to the
particular channel. At block 815, the particular channel may be changed to
synchronously
with all other access points in a mesh network.
[0083] Turning now to FIG. 9, another example of a method 900 is
illustrated.
The method 900 may be used by an access point to switch a transmission and/or
reception
channel simultaneously with all other nodes and devices in a communication
system.
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[0084] In the method 900, the device may be initialized in act 902. Each
device
in the system may, upon initialization in act 900, use a callback routine
(e.g., of a proprietary
kernel module) in act 904 to register a channel or channel switch. Thereafter,
the action
taken may depend on whether the device is starting a channel change request
(act 906a) or
receiving from another access point an indication that a channel change is to
occur (act 906b).
If the access point is initializing the channel change, it may determine that
a channel change
is necessary or desirable. This may occur by, for instance, performing a clear
channel
assessment as described hereafter, although the channel switch may be
determined in other
manners (e.g., through a local user interface). Starting a channel change
request in act 906
may include other acts, including determining what channel change to make and
what time
the change should occur. As discussed herein, the time at which the change is
to occur
should be sufficiently far in the future to allow messages to propagate
through the system and
allow all devices and nodes to change simultaneously.
[0085] The time function for changing channel may include a single value
corresponding to the time a channel should change. This value may be absolute
or relative as
described herein. In other embodiments, however, multiple values may be
specified. As an
example, the time function determined in act 906a through triggering of a
channel switch
event may include: (a) determining a time when a transmission queue should be
stopped; (b)
a time when the channel switch should occur; and (c) determining a time when
the
transmission queue should resume. In some embodiments, a flag or other value
may also be
set to indicate whether or not the transmission queue should resume at all. If
the access point
performing the method 900 is not initializing the channel switch, the access
point may instead
receive a message in act 906b. The message may include some or all of the
information
discussed above relative to act 906a, including channel identification
information, a time to
switch channels, how long before and after the switch to stop and resume the
transmission
queue, and flags (e.g., whether to resume the transaction queue at all). Some
channels (e.g.,
channels needing CAC, the flag may be set not to resume the transmission
queue).
[0086] Regardless of whether the access point is initiating the channel
change
(i.e., performing act 906a) or receiving a message indicating a channel change
should occur
(i.e., performing act 906b), the access point may add channel change
information to an
outgoing beacon message in act 908. An initiating access point may add the
information to a
new beacon, whereas a receiving access point may add received information to
its own
beacon. As discussed herein, the time information may be changed by a
receiving access
point to indicate relative times for changing a channel. Such relative times
may be changed
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to account for the time to receive and send a new beacon with the channel
change
information.
[0087] Adding the information in act 908 may also include adding channel
change
information in one or more manners. For instance, channel change information
may be
formatted according to a custom or proprietary structure of a kernel module.
Other channel
change information may be formatted according to a standard protocol. In some
embodiments, adding the information in act 908 includes adding channel change
information
in both proprietary and standard formats so that channel change information
may be
understood by access points and devices that understand either standard. While
FIG. 9
illustrates an act 908 of adding channel change information, in some
embodiments the
method 900 may be carried out by a station rather than an access point. In
such an
embodiment, the station may not send out beacons, and the act 908 may be
skipped.
[0088] Once an access point knows the channel change information,
whether
following determining the information and triggering a channel change in act
906a, or after
receipt of a channel change message in act 906b, the access point can set a
timer in act 910 to
cause the channel change to occur. Setting the timer in act 910 may include
setting up an
input and output control ("IOCTL") with relevant information for changing
channels. The
relevant information include what channel to change to and the time of the
change. Other
relevant information may include how long before and after the switch to stop
and resume
transmission queues, whether to resume a transmission queue at all, etc.
[0089] Before or after setting the time in act 910, the access point may
also send a
beacon that includes channel change information (act 912). Sending the channel
change
information may also include transmitting the message with the proprietary
(e.g., according
to proprietary kernel module) and/or standard (e.g., according to 802.11h CSA
standard) to
propagate the message to other devices. A receiving module may then receive
the message in
an act 906b and follow a method similar to the remainder of method 900.
[0090] The timer set in act 910 may fire at appropriate times based on
the
information used. In method 900, three timers may be set. These timers may
fire at
appropriate times and corresponding actions may take place. After time passes
and a first
timer fires in act 914, the method may include stopping a transmission queue.
Stopping the
transmission queue can be a pre-change event, and can optionally stop a
reception queue as
well. Completion of these tasks may be reported to the local host through an
interrupt, which
can stop radar when the timer fires in act 914.
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[0091] When the second timer fires in act 916, it may indicate a time to
switch
channels. As a result, the system may change channel/frequency to the
specified channel,
and inform the local host (e.g., through an interrupt). At that time the local
host may also
restart radar if necessary. Data structures (e.g., an 802.11 com data
structure) can be updated
with the current channel information. After that time, the third timer can
fire in act 918. The
third timer can trigger restarting of the transmission queue, and a
notification to the local host
through an interrupt or other manner.
[0092] If any locks have been set, the locks may also be released in act
920, and
work can be restarted to mark the process as complete. A registration
procedure may also be
performed in act 922. The registration procedure may include calling of a
callback. The
callback can be registered in some embodiments by a proprietary kernel module
to complete
the channel change procedure. Optionally, completed information may be
reported to other
access points, although in some embodiments the registration may be maintained
only
locally.
Clear Channel Assessment
[0093] The above discussion related to fast channel switching describes
an
embodiment of the present disclosure in which an access point of a mesh
network may
initiate a channel change by sending one or more messages to other access
points, and
allowing the other access points to propagate the message through the mesh
network to all
access points and stations. The following discussion relates to when and how
the initiating
access point may determine that a channel change is desirable. Accordingly,
aspects
disclosed below relating to clear channel assessment may be included within
the method 900
of FIG. 9, or in another suitable method. In accordance with one embodiment,
aspects of
clear channel assessment may be inserted between acts 904 and 906a.
[0094] A clear channel assessment may be performed in a number of
manners,
and can include various features. According to one embodiment, the clear
channel
assessment feature can include clear channel assessment ("CCA") and radar
detection. Using
radar detection, sample signals may be collected to determine if radar is
detected on a
particular channel. That information may then be provided to the caller,
whether the caller is
local on an access point, or is remote in another access point. The caller can
then determine
to take appropriate action. For instance, if radar is detected on a channel,
the action may be
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to change channels immediately (or to propagate a message to change channels
as quickly as
possible.
[0095] Generally speaking CCA can be used to measure the status of a
chipset
and determine whether one or more channels are available should a current
channel be
degrading. In one embodiment this may be performed by monitoring the status of
an RF
chipset. By way of illustration, a channel, and potentially a secondary
channel, may be
monitored and associated with a particular bit. If the RF power on a
respective channel is
below a predetermined threshold, the bit is asserted for the respective
channel. Different
values may thus be provided if the channel, or secondary channel, is clear as
opposed to when
the channel is not clear. While sampling may occur a single time, other
embodiments
contemplate sampling multiple times over a time period. Sampling multiple
times over a
given time period allows an access point or station to gather more information
about the
activity on a particular channel. The inverse proportion of samples where the
bit was asserted
can give a measurement of how busy the channel is. A relatively busy channel
may be less
desirable as a target channel for a channel switch as compared to a relatively
inactive
channel.
[0096] It should be noted that when a channel/frequency is monitored, a
device
may temporarily change to the channel to be monitored. Where sampling is
performed
multiple times over a longer period of time, the device may repeatedly and
temporarily
change to the sampled channel, then change back to the current channel.
Optionally, radar
detection may be done during the same CCA sampling period. Signal pulse
samples may be
collected to determine whether or not radar is present. Particularly where
each sampling
period is short, the use of multiple samples provides a greater ability to
detect whether or not
radar is present on the channel. Over time, data may be obtained for the
particular channel
being tested to determine its availability and usage, and if multiple channels
are sampled, a
range of usage data for all channels may be collected.
[0097] When other channels are available that provide more accessibility
than a
current channel, the initiating access point may initiate a channel switch as
described above.
The switch may be based on usage information collected at each of multiple
access points
and/or stations, rather than at a single device. Thus, each component in a
mesh network may
perform CCA and radar detection. Those results may be aggregated by an
initiating access
point to determine how each access point and station may respond to a
particular channel
change.
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[0098] In assessing a channel, CCA requests may be propagated to access
points
through a process similar to that described previously for a channel change.
Thus, a process
may include sending a proprietary and/or standard message to one or more other
access
points. The message may include information about which channel to test, the
time to test the
channel, and the like. In some embodiments, the process is similar but uses a
different
proprietary interface of a kernel module that also may describe information
such as the length
of a sample and the overall duration during which multiple samples are to be
taken, in
addition to information about the channel or channels to sample, and the times
for sampling
to occur.
[0099] Because a message may be propagated with time information, each
of the
access points may simultaneously test and measure activity on another channel.
A callback
routine may be used to then report and register the results with the access
point, and the
access point can then provide the information to others and to higher level
software for
collection. The higher level software or other devices may determine when a
channel change
should be made based on the collective, simultaneously obtained CCA and radar
information
from all access points in a network. In some embodiments, the output from a
CCA and radar
measurement may include: (a) the starting time; (b) the ending time: (c) the
number of
samples where a CCA bit is asserted for a primary channel; (d) the number of
samples where
a CCA bit is asserted for the secondary channel; (e) the number of times an
interface iterated
to collect samples; and (f) a Boolean value for whether or not radar was
detected at some
point during the sampling.
[00100] Sampling of channels for clear channel assessment purposes may also
use
similar information with respect to a TSF as that used by an access point
during a channel
switch. For instance, a custom interface may be provided on a beacon. The
custom,
proprietary interface may provide information such as timing on when to stop a
transmission
or receiving queue, when to change channel for sampling purposes and to
collect sampling
data, how often to repeat the sampling, how long each sample should be and the
total time
over which samples should be taken, when to restart a transmission and/or
receiving queue,
and the like. Various timers may therefore fire as shown in FIG. 9, which
timers may include
timers related to stopping and restarting a queue, and changing a channel.
Such timers may
also be iterated to allow sampling to occur multiple times over a longer
period. In at least
one embodiment, it is contemplated that no prior time is used or specified to
stop a queue.
Instead, the queue may be stopped at the time a channel change occurs, rather
than before.
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[00101] Although not intended to be limiting of the present disclosure, one
embodiment contemplates issuing a command as an IOCTL to a driver to fetch CCA
information on a channel. An example format of such a command may include:
call_qcsapi start_cca wifi0 44 40
Using this format, the driver may cause CCA information to be fetched on
channel 44
for a duration of 40 milliseconds. In some embodiments, the duration may be a
total duration
during which a channel should change to perform a CCA test. If, for instance,
it takes 20
milliseconds to perform a channel change, that may then leave only 20
milliseconds for the
sampling period to occur.
Chanel Scan
[00102] The above disclosure related to clear channel assessment contemplates
the
use of a proprietary or custom interface to propagate messages to test channel
availability on
one channel and potentially a secondary channel. Each device can perform the
test at the
same time. In other embodiments, however, sampling a channel may occur as part
of a
scanning process during which multiple channels may be sampled. Each of
multiple channels
may be sampled multiple times. The process may then iterate with additional
channels to
build up a scan table for all channels. The initiating access point may also
issue custom and
proprietary messages that allow for scanning. Such messages may include the
same
information used for scanning a single channel and/or secondary channel, but
may also
include information such as the number of additional channels to scan, an
identification of the
additional channels, timing information for the other channels, and the like.
[00103] As a scanning procedure may take longer than a scan of a single
channel,
an access point may dedicate its resources to sampling, and be off of a
primary channel used
for communication for a period of time. As the access point may not always
remain
connected to the primary channel, some packets can be lost, however, the
access point and
stations may remain associated. As with sampling a single channel, sampling
may be done
while accounting for time to switch channels. Such an accounting may include
the time to
change channels as well as a limitation on the cycles used. If too many cycles
are used, the
device software may trigger a reset, and limits on cycling may be used to
avoid the reset.
[00104] In view of the above description, it should be appreciated that
systems,
devices, and methods of the present disclosure may allow an access point in a
mesh network
to determine that a channel change is desirable (e.g., using CCA collected
from multiple
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nodes, radar detection, etc.), and propagate a message to all nodes for
simultaneously
changing the channel to avoid loss of data packets or disassociation between
nodes and
stations. Embodiments of the present disclosure may comprise or utilize a
special purpose or
general-purpose computer including computer hardware, such as, for example,
one or more
processors and system memory in an access point, a server, switch, or
computing device, an
end-user device, or in other systems or components.
[00105] Embodiments within the scope of the present disclosure also include
physical and other computer-readable media for carrying or storing computer-
executable
instructions and/or data structures. Such computer-readable media can be any
available media
that can be accessed by a general purpose or special purpose computer system.
Computer-
readable media that store computer-executable instructions are computer
storage media.
Computer-readable media that carry computer-executable instructions are
transmission
media. Thus, by way of example, and not limitation, embodiments of the
disclosure can
comprise at least two distinctly different kinds of computer-readable media,
including at least
computer storage media and/or transmission media. Computer-readable media that
includes
computer-executable instructions may also be referred to as a computer program
product.
[00106] Examples of computer storage media include RAM, ROM, EEPROM,
CD-ROM or other optical disk storage, magnetic disk storage or other magnetic
storage
devices, flash-based storage, solid-state storage, or any other physical, non-
transmission
medium which can be used to store desired program code means in the form of
computer-
executable instructions or data structures and which can be accessed by a
general purpose or
special purpose computer.
[00107] When information is transferred or provided over a communication
network or another communications connection (either hardwired, wireless, or a
combination
of hardwired or wireless) to a computing device, the computing device properly
views the
connection as a transmission medium. A "communication network" may generally
be defined
as one or more data links that enable the transport of electronic data between
computer
systems and/or modules, engines, and/or other electronic devices, and
transmissions media
can include a communication network and/or data links, carrier waves, wireless
signals, and
the like, which can be used to carry desired program or template code means or
instructions
in the form of computer-executable instructions or data structures within, to
or from a
communication network. Combinations of storage media and transmission media
should also
be included within the scope of computer-readable media.
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[00108] Further, upon reaching various computer system components, program
code means in the form of computer-executable instructions or data structures
can be
transferred automatically from transmission media to storage media (or vice
versa). For
example, computer-executable instructions or data structures received over a
network or data
link can be buffered in RAM within a network interface module (e.g., a "MC"),
and then
eventually transferred to computer system RAM and/or to less volatile computer
storage
media at a computer system. Thus, it should be understood that computer
storage media can
be included in computer system components that also (or even primarily)
utilize transmission
media.
[00109] Computer-executable instructions comprise instructions and data which,
when executed at a processor, cause a general purpose computer, dedicated or
special
purpose computer (e.g., an access point), or special purpose processing device
to perform a
certain function or group of functions. The computer executable instructions
may be, for
example, binaries, intermediate format instructions such as assembly language,
or even
source code. Although the subject matter has been described in language
specific to
structural features and/or methodological acts, it is to be understood that
the subject matter
defined in the appended claims is not necessarily limited to the described
features or acts
described above, nor performance of the described acts or steps by the
components described
above. Rather, the described features and acts are disclosed as example forms
of
implementing the claims.
[00110] Those skilled in the art will appreciate that the embodiments may be
practiced in network computing environments with many types of computer system
configurations, including, personal computers, desktop computers, laptop
computers,
message processors, hand-held devices, programmable logic machines, multi-
processor
systems, microprocessor-based or programmable consumer electronics, network
PCs, tablet
computing devices, minicomputers, mesh network access points or nodes,
mainframe
computers, mobile telephones, PDAs, pagers, routers, switches, and the like.
[00111] Embodiments may also be practiced in distributed system environments
where local and remote computer systems, which are linked (either by hardwired
data links,
wireless data links, or by a combination of hardwired and wireless data links)
through a
network, both perform tasks. In a distributed computing environment, program
modules may
be located in both local and remote memory storage devices.
[00112] Those skilled in the art will also appreciate that embodiments of the
present disclosure may be practiced in special-purpose, dedicated or other
computing devices
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integrated within or particular to a particular residence, business, company,
government
agency, or other entity, and that such devices may operate using one or more
network,
wireless, hardwire, or other connections, or any combination thereof. Examples
may include
residential or commercial buildings in connection with a mesh network
providing access to a
service provider (e.g., an ISP).
[00113] Although the foregoing description contains many specifics, these
should
not be construed as limiting the scope of the disclosure or of any of the
appended claims, but
merely as providing information pertinent to some specific embodiments that
may fall within
the scopes of the disclosure and the appended claims. Various embodiments are
described,
some of which incorporate differing features. Any feature illustrated or
described relative to
one embodiment is interchangeable and/or may be employed in combination with
features of
any other embodiment herein. In addition, other embodiments may also be
devised which lie
within the scopes of the disclosure and the appended claims. The scope of the
disclosure is,
therefore, indicated and limited only by the appended claims and their legal
equivalents. All
additions, deletions and modifications to the disclosure, as disclosed herein,
that fall within
the meaning and scopes of the claims are to be embraced by the claims.
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