Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02320573 2000-09-25
FIELD OF THE INVENTION
The present invention relates generally to wireline and wireless
telecommunication systems as well as broadband access networks; and more
S particularly to a telecommunication system capable of providing broadband
voice and
data services in both wireline and wireless applications via at least one
shared
broadband access network.
BACKGROUND OF THE INVENTION
Wireless technology has come a long way since the deployment of the first
generation (1G) analog system. With efforts of deployment of the second
generation
(2G) and third generation (3G) mobile systems, the mobile telecommunication
service has not only offered the voice service but also fast data service.
There are
variety of technology options to choose from for radio access, namely TDMA,
GSM,
CDMA, W-CDMA, and etc.
Due to limited bandwidth of wireless spectrum allocation, each cell can
usually only support handful of wireless subscribers, especially high data
rate
subscribers. In order to provide services to increasing number of wireless
subscribers
and meet the strong demands of high-speed wireless services, especially in
metropolitan areas, wireless service providers usually have to deploy latest
equipments to increase the service bandwidth of each cell site, but
ultimately,
wireless service providers have to increase the number of cell sites to cover
the
same geographic area, and increase the bandwidth of public land mobile network
(PLMN). This may require complex planning and engineering effort, building
more
cell site towers, adding new base station equipments, and adding more E1/T1 or
fiber
optic connections between base transceiver station (BTS) to a base station
controller
(BSC) or mobile switching center (MSC). The cost of deploying such
infrastructure is
usually enormous, and the cost has to be justified by wireless services. This
is one of
the main reasons why the high-speed wireless services are still very expensive
for
average mobile subscribers.
Besides mobile telecommunication services, Wireless Local Area Network
(WLAN) and Wireless Personal Area Network (WPAN) services have also gained
popularity these years with easy deployment and promising high-speed wireless
Internet access. A WLAN and WPAN can operate at 900 MHz and 2.4/5 GHz
Industrial, Scientific, and Medical (ISM) bands. However, acquisition costs
are not
low particularly when compared to wired LANs, and conventional WLAN stations
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(STA) are restricted to operate in a small coverage area and may only have
limited
roaming ability within the same LAN configuration. On a WLAN system which is
data
packet based, stations have not enjoyed the same level of global roaming and
voice/data services that is commonly available by mobile telecommunication
systems.
To address the need for speed, broadband transport and access technologies
are rapidly being deployed in backbone networks and access networks of large
end
users. There is a variety of broadband network infrastructure built or being
built to
meet increasing bandwidth demand. Some broadband technologies are intended
specifically for data or voice transmission, others are designed to support a
full range
of audio, data, video, and image traffic. The most common access technologies
include generic Digital Subscriber Lines (xDSL) and Community Antenna
Television
(CATV) cable modems to provide subscribers with high-speed Internet access.
xDSL is a group of technologies applied to unshielded twisted pair (UTP) local
loop,
including Asymmetric DSL (ADSL, 6.992.1 or 6.992.2), High-Bit-Rate DSL (HDSL
or
HDSL2), Symmetric DSL (SDSL or SDSL2), ISDN DSL (IDSL), Rate-Adaptive DSL
(RADSL), and Very-High-Data-Rate DSL (VDSL). Additionally, fiber and Wireless
Local Loop (WLL) technologies have also been developed to extend broadband
capabilities to the premise. The fiber technologies include Synchronous
Optical
Network (SONET) and Synchronous Digital Hierarchy (SDH), and User Network
Interface (UNI) has been defined for the premise to connect to a SONET or SDH
network. Popular WLL technologies include Local Multipoint Distribution
Services
(LMDS), Multichannel Multipoint Distribution Services (MMDS), and licensed
microware links. The enhancements of above access technologies can support not
only high-speed data but also additional telephone services to the Customer
Premises Equipment (CPE).
The above broadband networks are designed to support wireline services, not
directly connected to a wireless service access node, such as a base station.
Therefore they do not carry wireless traffic.
Here is a scenario: An xDSL subscriber is always limited to the maximum
xDSL access bandwidth, some services such as Movie-On-Demand (MOD) may not
be available to the subscriber due to the xDSL bandwidth limitation. Even
though
his/her neighbors are not using their xDSL services at the time. It would be
nice for a
subscriber to be able to utilize the unused access bandwidth of neighboring
xDSL
connections, therefore a subscriber would no longer limited to his/her own
xDSL
connection.
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Here is another scenario: A mobile subscriber receives a mobile phone call at
a friend's house, the received Radio Frequency (RF) signals are transmitted
from a
base station probable a few kilometers away, and the mobile station has to
transmit
RF signals back to the base station. Due to large mobile power transmission,
the
mobile battery has to be recharged every few days. It would be nice for the
mobile
subscriber to receive the same call, however the RF signals are transmitted
from the
home base station that has xDSL access, and the mobile station can communicate
with the base station at an extremely low power level. The battery life of the
mobile
can last for weeks.
It would be nice to have a united network system to cope with both wireline
and wireless services at the same time, one system is needed for all services.
It
would be even nicer to have the system deploy in a fast and cost-effective
way.
Accordingly, there is a strong need for an economical deployment of wireless
telecommunication systems and enhancements of mobile services. The services of
wireless LAN (WLAN) should be extended to have voice call and global roaming
ability, which makes it possible for wireless LAN (WLAN) technologies to
compete
with existing mobile telecommunication services. Bandwidth sharing among
access
nodes and different access networks will clearly be more effective way to
provide
high-speed Internet access to end users. It would be a strong demand to deploy
a
united network system to offer both wireline and wireless services to end-
users at an
affordable prize.
The present invention is to deal with the above issues. According to the
invention, the Universal Telecommunication System (UTS) will provide the
simple
and cost-effective solution to the previous system limitations. The deployment
cost of
such system can further be justified among a wide range of wireline and
wireless
services.
SUMMARY OF THE INVENTION
The first object of the present invention is to provide an integrated wireline
and wireless telecommunication system, hereinafter referred to as Universal
Telecommunication System (UTS). The UTS consists of at least one integrated
wireline and wireless switching centers, hereinafter referred to as Core
Network
Center (CNC). Each CNC connects to a plurality of base stations, hereinafter
referred
to as Universal Access Node (UAN), that provide network access services to a
plurality of wireline and wireless devices. According to the present
invention, the UTS
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deployment is a cost-effective and efficient means of offering true broadband
voice
and data services to both wireline and wireless subscribers, especially in
metropolitan areas.
The second object of the present invention is to provide a means of accessing
multiple broadband networks simultaneously from a single Customer Premises
Equipment (CPE). A Universal Access Node (UAN), or a "Base Station" some may
prefer to call it, with built-in intelligence, is capable of handling variety
of voice and
data traffic to different networks.
According to the present invention, there is provided a typical Universal
Access Node (UAN) with multiple network interfaces, namely an xDSL, a CATV
cable, a fiber connecter, a Local Multipoint Distribution Services (LMDS) or
Multichannel Multipoint Distribution Services (MMDS), a Low-Earth Orbiting
satellites
(LEOs) or Middle-Earth Orbiting satellites (MEOs), and an Ethernet, which
enable
UAN to access to different high-speed networks at the same time. The UAN can
route traffic from one network to another through two different network
interface. The
UAN also has RF modules for wireless accesses and multiple phone, fax,
Ethernet,
and USB connectors for SOHO and Home Area network (HAN) services.
According to the present invention, there is provided a UAN with which data
traffic can be directly routed to other networks without going through the CNC
or
mobile switching center (MSC) in conventional mobile telecommunication
systems.
Here is a scenario: Other than the high speed link connected to the CNC, say a
UAN
also has a connection to CATV network. The Universal Telecommunication (UTS)
service provider can lease a group of internal IP addresses (not necessary
permanent IP addresses) from the CATV networks provider (not necessary a
wireless service provider). The CNC can assign one of the addresses to a
mobile
station (MS), the mobile data will be routed to the CATV head-end by the UAN,
and
from there to a packet data network (PDN), CNC only keeps track the quality-of-
service of the data channels through the UAN Traffic Controller (UANTC). The
same
principle can be applied to a wired device.
The third object of the present invention is to provide a means of optimizing
the bandwidth usage among different access technologies within a single CPE by
sharing the bandwidth among different wireline and wireless services.
According to the present invention, there is provided a means of providing
access bandwidth combination to a residential and SOHO (small office and home
office) subscriber with voice and high-speed data services. A Universal Access
Node
(UAN) can combine all the available access bandwidth from xDSL, CATV cable,
Low-
Earth Orbiting satellites (LEOs), and WLL access technologies, so that the
subscriber
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maximum access bandwidth is not limited to a single access technology, unlike
a
conventional broadband service.
The fourth object of the present invention is to provide a means of optimizing
the overall access network performance by sharing broadband access connections
among neighboring CPEs. This way individual CPE can gain additional access
bandwidth by making use of the unutilized access bandwidth of its neighboring
CPEs
by routing some packets to its neighboring high-speed connections through its
predetermined air interfaces.
According to the present invention, more access bandwidth can be obtained
by combining with neighboring UANs through an air interface. The subscriber
can
effectively obtain the combination of all access technologies and all the high-
speed
access links in the neighborhood.
According to the present invention, there is provided a UAN, capable of
communicating with its neighboring UANs via air interfaces, and capable of
routing
traffic to its neighboring UANs. In a typical configuration, a UAN is able to
communicate with its neighboring UANs like a mobile station (MS) belong to
these
cells, UANs are capable of inter-cell relay, passing traffic from one to
another. In a
typical wireless LAN (WLAN) application, a UAN can operate at two frequencies
simultaneously, although it operates at one frequency channel as an access
point
(AP) for its cell coverage area, however at the same time, it can also
communicate
with an adjacent cell access point (AP) or wireless LAN station (STA) at a
different
frequency, functioning like a station (STA) in the adjacent cell. The same
principle
may be applied to a typical cellular application as long as two adjacent cells
cannot
operate at the same frequency. A UAN can operate as a regular base transceiver
station (BTS), and at the same time the UAN can transmit packets to its
neighboring
UANs through its Forward Channels and receive packets from its neighboring
relay
UANs on its Reverse Channels; Each UAN is able to transmit at least two
frequencies, one is the UAN cell forward link frequency and the other is a
neighboring UAN reverse link frequency. Each UAN is also able to receive at
least
two frequencies, one is the UAN cell reverse link frequency and the other is a
neighboring UAN forward link frequency. Such UANs can relay traffic from one
UAN
to another UAN and go on. For some cellular systems that the same frequency is
reused by adjacent cells, such as in CDMA systems, a UAN has to shut down its
cell
site services before it can communicate to a neighboring UAN via the forward
link
and reverse link channels of the neighboring UAN.
The fifth object of the present invention is to provide an economical solution
to
leverage a given broadband access network infrastructure to allow service
providers
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to derive additional revenue from wireless services, such as Wireless-Over-DSL
(WoDSL), Wireless-Over-Cable (WoC), and Wireless-Over-Fiber (WoF). The
invention takes advantage of the existing high-speed access to the residential
or
downtown office area, and effectively deploys additional wireless services at
a very
low cost. The high-speed connections can be dynamically shared by both
wireline
and wireless services.
The sixth object of the present invention is to provide a wireless LAN (WLAN)
or Wireless Personal Area Network (WPAN) system that offers global roaming and
voice call services, which are beyond what a conventional WLAN/WPAN system can
offe r.
According to the present invention, a wireless LAN station (STA) is capable of
global roaming with or without a permanent IP address. According to the
present
invention, each wireless LAN station (STA) is assigned a unique STA global ID
and a
directory number (DN) just like a mobile ID and a directory number for a
cellular
phone, the global ID could be simply an International Mobile Station Identity
(IMSI)
defined by the International Telecommunication Union (ITU). The network
maintains
association between the mobile's ID and the mobile's directory number.
Therefore a
wireless LAN system and a cellular system can share the existing cellular
network
database. During the authentication in a visitor location, the STA identifies
its global
ID to the visited Core Network Center (CNC). According to the global ID,
visited Core
Network Center (CNC) can query the STA Home Location Register (HLR) database
to obtain the STA profile. The HLR is a database entity in which the main
database
entry of a STA resides. The HLR contains the STA's profile, STA user interface
information, current status, and location information. From the STA's profile,
the
visited CNC obtains the Shared Secret Key and sends it to the universal access
node
(UAN) which function as an access point (AP) in the wireless LAN system. The
UAN
continues to perform Shared Key authentication with wire equivalent privacy
(WEP)
encryption or a proprietary encryption. The Shared Secret Key is unique and
only
known by the STA and the network. Once the STA is successfully authenticated,
the
HLR and VLR entries will be updated to indicate where the STA is being
serviced.
The HLR and VLR are usually required for some of the IS-41 operations. The HLR
and VLR together govern the location and status of the STA. When a STA moves
from one CNC to another CNC, the VLR keeps track of the STA by gathering
information from the HLR through STA association. If the STA does not have a
permanent IP address registered in the HLR profile, the visited CNC can assign
a
dynamic IP address to the STA. If the mobile have a permanent address
registered in
the HLR profile, the STA may be given a choice of using its permanent address
or a
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dynamic address. If the STA chooses to use its permanent address, the STA
incoming data traffic will be routed to the home CNC first, and then
redirected to the
visited CNC, the out going traffic is not necessary to be routed to the home
CNC.
After the STA is associated with the AP, the STA is able to engage a regular
voice
call like a mobile telephone. The Access Point may be required to use the
Point
Coordination Function (PCF) described in the IEEE Std 802.11 to provide voice
call
services. A virtual circuit channel (VCC) can be set up between the STA and
the
CNC, from the CNC, it connects to the public switched telephone network
(PSTN).
The STA can be configured with different voice coding schemes dependent on the
services availability.
The seventh object of the present invention is to provide a means of global
roaming and handoffs among cells (inter-UAN), central switches (inter-CNC),
and
services (inter-Service). The Inter-Service handoff is a handoff between two
types of
mobile services, such as cellular and WLAN. Such Inter-Service handoffs
require that
a dual-mode mobile station to support cellular and Wireless LAN services. The
mobile station may enjoy not only global roaming, inter-cell handoff, inter-
system
handoff, but also inter-service handoff. The mobile station may be handed off
from a
cellular service to a Wireless LAN service, and vice versa.
The eighth object of the present invention is to provide an efficient means of
deploying wireless services to geographical areas with different types of
broadband
access technologies, namely Digital Subscriber Loop (DSL), CATV network,
optical,
and Wireless Local Loop (WLL) technologies.
The ninth object of the present invention is to provide small-cell wireless
systems with large number of cells and each cell only cover a very small and
high
subscriber density area, such as one or two homes of a neighborhood, each
floor of
a building, corner of a pedestrian street, a hotel lobby, and etc. The power
consumption of a mobile can be largely reduced and a mobile call can be easily
located.
According to the present invention, there is provided a small-cell system that
E-911 and other emergency calls can easily be located. With the help of a look-
up
table or a proprietary algorithm, a Core Network Center (CNC) can calculate
the
approximate MS location according to the strength measurements results, which
records the MS received signals from acting UAN and the adjacent UANs during
the
emergency call.
The tenth object of the present is provided a CPE with more than one
physical link to communicate with the central office. According to the present
invention, there is provided a Universal Telecommunication System (UTS) in
which a
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UAN can connect to the CNC via alternative high-speed physical links. When a
main
high-speed link (say xDSL) is down, the UAN can still communicate with the CNC
by
first transmitting the control and alarm signaling together with the rest of
the traffic to
a neighboring UAN via an air interface, and then the neighboring UAN routes
the
signals to the CNC through its main high-speed link. Therefore the quality of
service
(QoS) can be maintained. This feature is very important for ADSL (6.992.2 and
6.992.2) links. The quality of such high-speed connections may degrade over
time,
the links need to be retrained to achieve the maximum bandwidth performance.
However, the retraining events such as Dynamic Rate Repartitioning (DRR),
Dynamic Rate Adaptation (DRA) and fast retrain may result interruption of
voice and
isochronous data cervices. Therefore, the Universal Access Node Traffic
Controller
(UANTC) inside each UAN is responsible to coordinate these events. If voice
services are in progress, the UAN may hold-off retrain until the phone calls
finish. If
the DSL link quality is continuously degraded to a very low margin level, the
UAN
sends an alarm signal to the CNC, the CNC receives the alarm and sets up an
air
link to the base station through an adjacent cell. The UAN can route voice
calls to the
adjacent UAN through the air interface. After the calls are successfully
rerouted to
the adjacent UAN, the UAN can start the DSL link retrain process.
The tenth object of the present is provided a Universal Telecommunication
System (UTS) that offers a variety of telemetry type of services. The CNC
store the
service subscriber database and the UANs provide wired and wireless interfaces
to
the services. These services can be easily provided due to most of the UANs
are
close to residential and downtown office areas. Such wide ranges of services
cannot
be completely listed here. As some examples of the typical applications can be
easily
associated with these services, such as periodical hydro, gas, water, and
parking
meters reading, wireless camera and camcorder, house alarm, security systems
with
separate voice and video features, etc.
The eleventh object of the present is to provide a wireless system with
flexible
base station configurations to support space and frequency diversities
services.
According to the present invention, there is provided a Universal
Telecommunication
system (UTS), in which two or more adjacent Universal Access Nodes (UANs)
together can be configured to form a cell site and offer frequency and space
diversities to a mobile station (MS) as an optional service.
The twelfth object of the present is to provide a wireless system with
advanced voice mail service. According to the present invention, there is
provided a
Universal Telecommunication system (UTS) with Voice Mail System (VMS) that can
deliver voice mail messages as compressed data packets to a mobile subscriber
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without dialing a phone number to check the messages. When a mobile station
(MS)
is turned on to register the service, all the voice mail recorded at the home
Core
Network Center (CNC) VMS database can be automatically compresses and
downloaded to the local serving CNC (could be a visitor CNC). The serving CNC
can
indicate the number and sizes of the messages to the MS. The MS can choose to
download immediately or wait until cheaper high-speed services are available.
The
MS can choose to download the messages with a different wireless interface,
then
decompress and listen to the messages without dialing a number to a Voice Mail
Center. This feature could be an enhancement to the current mobile
communication
systems.
The thirteenth object of the present is to provide a wireless system with
advanced fax mail service. According to the present invention, there is
provided a
Universal Telecommunication system (UTS) with Fax Mail System (FMS) that can
deliver fax mail messages as compressed data packets to a mobile subscriber
without a mobile fax machine. When a fax message is sent to a mobile station
number, the home Core Network Center (CNC) recognizes that it is from a fax
machine, then receive the fax data and store it to the home FMS. When a mobile
station (MS) is turned on to register the service, all the fax mail recorded
at the home
CNC FMS database can be automatically compresses and downloaded to the local
serving CNC (could be a visitor CNC). The serving CNC can indicate to MS the
number and sizes of the messages. The MS can choose to download immediately or
wait until cheaper high-speed services are available. The MS can choose to
download the messages with a different wireless interface, then decompress and
listen to the messages without an actual built-in fax machine. This feature
could be
an enhancement to the current mobile communication systems.
The fourteenth object of the present is to provide a network center, Core
Network Center (CNC), that is connected to public switched telephone network
(PSTN) and packet data network (PDN). A CNC supports multiple wireline and
wireless services, is more than a simple combination of a local telephone
Central
Office (CO) and a Mobile Switching Center (MSC). The unique network
architecture
allow a CNC to provide more bandwidth and better services to wireline Customer
Premises Equipment (CPE) than a traditional local CO, and support multiple
wireless
services with the same low-power base station, referred to as Universal Access
Node
(UAN) in the present invention. A CNC not only supports inter-cell (or inter-
BTS),
inter-system (or inter-switch) handoffs like previous mobile systems, but also
supports inter-service handoffs, such as handoffs between digital mobile
station (MS)
to a Wilreless LAN station (STA) and vice versa. A CNC can also support voice
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services to a Wireless LAN (WLAN) or Wireless Personal Area Network (WPAN)
station.
The fifteenth object of the present is to provide a Wireless Local Area
Network (WLAN) or Wireless Personal Area Network (WPAN) station (STA) design
with built-in standard or proprietary Voice Coders, such as 6.711, 6.726,
6.729, and
etc. When the STA is connected to a WLAN that can access to a Voice Gateway to
a
Public Switched Telephone Network (PSTN) or Integrated Services Digital
Network
(ISDN), the STA can obtain voice call services via the Voice Gateway. It will
be
understood that the voice coding scheme used by the STA should be supported by
the Voice Gateway and a phone number has to be assigned to the STA.
According to the present invention, within a Universal Telecommunication
System (UTS), a STA device is able to obtain voice call services from a Core
Network Center (CNC) through the Universal Access Node (UAN) that is connected
to the STA. The STA voice call can be handed off to a neighboring cell by the
CNC,
and the STA voice call can also be handed off from WLAN/WPAN system to another
wireless system, such as to a cellular device.
The sixteenth object of the present is to provide the Universal Access Node
Traffic Controller (UANTC) in each Universal Access Node (UAN). UANTC is a
cross-layer coordination control function implemented by a micro-controller,
coordinating voice and data packets from wireline and wireless services based
on
cross-layer information provided by each network interface. UANTC makes the
best
effort to optimize high-speed link bandwidth usage and at the same time
monitors
each link quality and reports alarms to the Core Network Center (CNC). UANTC
not
only prioritizes various traffic types but also monitors packet delay, packet
queuing
conditions, and bandwidth margins, etc. UANTC is usually configured to handle
voice
and signaling packets with higher priority than normal data packets. The
control
signaling packets may be repeated for several times while being sent to the
CNC on
a less reliable link. Voice packets are usually handled with minimum delay but
also
minimum data protection. Normal data packets can tolerate large delay but very
few
errors, the data should be carefully protected for transmission. Voice packets
are
always given priority over normal data packets, data packets are chosen to
transmission only when there are no voice packets waiting in the queue.
Wireless
voice packets should have higher priority over voice packets from wired
devices.
UANTC monitors each traffic channel performance, records statistic
measurements,
and reports the results to the CNC. These activities help the CNC to learn the
traffic
patterns of wireline and wireless services in order to optimize the overall
system
performance. UANTC also tries to minimize incidences that multiple voice
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arrive in the queue at roughly the same instant (or voice packets collision),
by
managing each encoder timing of the active voice channels.
The seventeenth object of the present is to provide a method for acquiring
timing information for base stations in a synchronous wireless system. In a
synchronous mobile telecommunication system (IS-95, CDMA 2000, and etc), each
base transceiver station (BTS) has to be synchronous with others in operation.
In a
convention design, a Global Positioning System Receiver (GPSR) is required in
each
BTS. According to the present invention, one Master Universal Access Node
(MUAN)
can cover a larger area (macro/micro cell) which is overlaid on top of
multiple Slave
Universal Access Node (SUAN) coverage areas (micro/pico cells). Only a MUAN
needs a GPSR, the SUANs can acquire timing information from the MUAN, the
total
delay from a MUAN transmission to the SUAN timing recovery is calibrated for
each
SUAN at initial system deployment commissioning. The GPSR block may not be
included in a SUAN design. Therefore, the cost of a SUAN can be greatly
reduced.
The same principle can be applied to a conventional synchronous mobile system
as
a base station cost-reduction feature. Any regular BTS can be a Master BTS to
broadcast timing information to the SUANs. However, the Slave BTS design is
required to remove the GPSR block, modify the hardware timing reference
circuits,
and redesign the software to support the timing recovery feature.
The seventeenth object of the present is to provide a method of saving power
and reducing co-channel interference among Slave Universal Access Nodes
(SUANs). According to the present invention, a SUAN cell may be shut down into
Sleep mode (receive only mode) or waken up to normal Operation mode by the
commands from a Core Network Center (CNC). A SUAN may be shut down when
there are no mobile subscribers currently in service within the cell. When the
indoor
traffic of the Small Office or Home Office (SOHO) has approached the maximum
bandwidth of the total high-speed connections within the SUAN, the SUAN may be
requested to hand off all the serving mobile stations (MS) to the adjacent
cells and
shut down the cell site service afterward. The modes of a UAN are dynamically
configurable by the CNC. The same principle can be applied and implemented to
a
conventional mobile telecommunication system.
The eighteenth object of the present is to provide a method of passing data
from one base station to another base station through air interface. According
to the
present invention, there is provided a Universal Access Node (UAN) that can be
set
to Handover mode. In Handover mode, a UAN communicates with its neighboring
UAN's like a normal mobile station (MS), after the UAN has established a
communicate link with one of its neighboring UAN, the traffic can be routed
from
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Handover mode UAN to the neighboring UAN air interface. The Handover mode is
available in both cellular and Wireless LAN (WLAN) systems.
The nineteenth object of the present is to provide a base station, called
Universal Access Node (UAN), which can maintain only the required services
during
a power outage. A UAN usually has a backup battery to maintain some of the
services for short period of time. When a UAN experience a power surge, the
UAN
report the incidence to Core Network Center (CNC) through an alarm signal.
After
receiving the alarm, the CNC sends the action commands back to the UAN. The
UAN maintains only the services according to the CNC commands. The CNC has the
overall picture of the affected services and the type of services. The UAN may
be
asked to reduce the cellular or Wireless LAN (WLAN) transmission power to a
minimum level or simply shut down the whole cell site services. When there is
a
cellular E-911 call in process, the UAN may be asked to maintain or hand off
the call
first before shutting down the cell site services. The UAN may be asked to
switch
some of the telephones to the same Plain Old Telephone Service (POTS) (0-4KHz)
of the analog local loop to save UAN power. Some of the network interfaces may
be
shut down immediately due to large power consumption. The Wireless Personal
Area
Network (WPAN) services may not be affected, the power required to these
services
is usually low.
The nineteenth object of the present is to provide a method of minimizing the
impact to voice quality due to voice packet loss or errors over the high-speed
link.
When the bandwidth on the high-speed link is being under-utilized, the Core
Network
Center (CNC) may dynamically configure the Universal Access Node Traffic
Controller (UANTC) inside the UAN to use better voice quality coding schemes
for
voice services or send extra copies of voice packets to CNC to minimize the
impact
due to link errors and packet loss. Most of the wireless voice packets have
already
been compressed, in this case, extra copies could be sent to the CNC by the
UAN.
The nineteenth object of the present is to provide a means of providing low-
power wireless telecommunication services. The Universal Access Node (UAN) can
support low-power wireless device services with Wireless Personal Area Network
(WPAN), HomeRF, Bluetooth, and other indoor wireless technologies. Just like a
cellular phone service, a subscriber will be assigned a unique ID to his/her
low-power
wireless device, a special firmware may also be needed for the device. The
device ID
will be registered in a subscriber profile stored in a Core Network Center
(CNC)
Home Location Register (HLR) database. Low-power wireless devices, once
subscribed the services, can connect directly to wireless networks with high-
speed
access without connecting through a cellular device. The low-power wireless
devices,
12
CA 02320573 2000-09-25
such as Wireless Personal Digital Assistants (PDAs), can logon to the network
in any
location in the world where the UAN low-power services are available. Such low-
power wireless applications are without limits.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of the invention will now be described with reference to the
accompanying drawings wherein:
Figure 1 is a diagram of a conventional broadband telecommunication
system.
Figure 2 shows a diagram of conventional mobile telecommunication system
in the upper portion of the figure. Figure 2 also shows a diagram of a
Wireless Local
Area Network (WLAN) and a Wireless Personal Area Network (WPAN) in the lower
portion of the figure.
Figure 3 is a diagram of a typical Universal Telecommunication System (UTS)
according to the present invention.
Figure 4 is a block diagram of a typical Universal Access Node (UAN)
according to the present invention.
Figure 5 is a schematic diagram of a typical Universal Telecommunication
System (UTS) based on xDSL access technologies.
Figure 6 is a schematic diagram of a typical Universal Telecommunication
System (UTS) based on coaxial cable access technologies.
Figure 7 is a schematic diagram of a typical Universal Telecommunication
System (UTS) based on optical fiber access technologies.
Figure 8 is a schematic diagram of a typical Universal Telecommunication
System (UTS) based on Multichannel Multipoint Distribution Services or Local
Multipoint Distribution Services (MMDS/LMDS) access technologies.
Figure 9 is a schematic diagram of a typical Universal Telecommunication
System (UTS) based on Low-Earth Orbiting satellites or Middle-Earth Orbiting
satellites (LEOs/MEOs) access technologies.
Figure 10 is a conceptual diagram of Handover mode in a Universal
Telecommunication System (UTS).
Figure 11 is a conceptual diagram of Relay mode in a Universal
Telecommunication System (UTS).
Figure 12 is a conceptual drawing of inter-cell handover between two
Universal Access Nodes (UANs) in Wireless Local Area Network (WLAN)
applications.
13
CA 02320573 2000-09-25
Figure 13 shows the procedures of a typical inter-cell handover in Wireless
Local Area Nefirvork (WLAN) applications.
Figure 14 is a conceptual drawing of inter-system handover between two
Universal Access Nodes (UANs) in Wireless LAN applications.
Figure 15 shows the procedures of a typical inter-system handover in
Wireless Local Area Network (WLAN) applications.
Figure 16 shows a conceptual diagram of a typical arrangement of a
Universal Telecommunication System and an existing mobile telecommunication
system.
Figure 17 is a diagram of the three different modes for mobile
telecommunication applications available in a Slave Universal Access Node
(SUAN).
Figure 18 is a diagram of the four different modes for Wireless Local Area
Network (WLAN) applications available in a Universal Access Node (UAN).
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 is the architectural diagram of conventional broadband access
services in metropolitan areas. Between Central Office (CO) 203 and a Customer
Premises Equipment (CPE) device 302, there is a Regional Broadband Access
Network (RBAN) that provides CPE devices with high-speed connections. The CO
203 further connects to circuit and data switches to provide voice and data
services.
It will be understood that, in some network architectures, the unit 203 may be
named
differently, it is usually referred as Head End office in a Community Antenna
Television (CATV) network. The Customer Premises Equipment (CPE) device 302 is
typically located at Small Office, Home Offices (SOHO), or residential home,
it
connects to a plurality of voice and data devices via standard intertaces 206.
The
home and office devices may include a Plain Old Telephone (POTS) 131, regular
phones 132, fax machines, printers, computers 133, and etc. The high speed
connection 203 to the CPE device 302 could be a Digital Subscriber Line
(xDSL),
Community Antenna Television (CATV) cable, Wireless Local Loop (WLL), or even
fiber optic connection. However each network architecture has its own service
definitions, and each high speed connection requires a specific CPE device,
the CPE
device is usually not interoperable in different access networks. These CPE
devices
mainly perform Customer Premises Interworking Function (CP-IWF) and very
limited
network intelligence is needed inside them, these devices are often referred
as
"modems". The availability and quality of the SOHO wireline services, such as
Music-
14
CA 02320573 2000-09-25
On-Demand (MOD) and Video-On-Demand (VOD) services, are usually limited to the
maximum access bandwidth of the particular high-speed connection.
Figure 2 illustrates some of the popular conventional wireless
telecommunication services today. In the cellular system implementation,
illustrated
generally at 311, each Base Transceiver Station (BTS) 312 usually services a
plurality of Mobile Stations (MS) 135, and multiple Base Transceiver Stations
(BTS)
312 may connect to a Base Station Controller (BSC) 317 via backhaul E1/T1
connections 314, the backhaul T1/E1 links usually operate in unchannelized
mode.
Multiple of Base Station Controllers (BSC) can be connected to a Mobile
Switching
Center (MSC) 313 where the voice and data backbone networks accesses are
available. In some cellular systems, the Base Station Controllers (BSC) 317
are
integrated into a Mobile Switching Center (MSC) 313, the Base Transceiver
Stations
(BTS) can directly communicate with a Mobile Switching Center (MSC). A mobile
communication system may consist of at least one, but could be more than one
Mobile Switching Centers (MSC) 313 interconnected via a Public Land Mobile
Network (PLMN).
The implementation of Wireless Local Area Network (WLAN) and Wireless
Personal Area Network (WPAN) types of networks is illustrated generally at
322. In
Wireless LAN (WLAN) applications, WLAN stations (STA) 136 connect to a
Distribution System (DS) via an Access Point (AP) 315. Through Distribution
System
(DS) Portal, the stations (STA) 136 can connect to a wired LAN, and the
services
such as Internet access can be provided from the wired LAN. Each Access Point
(AP) 315 can service a plurality of WLAN stations. Within the same LAN, a
station
(STA) 136 may be handovered from one Access Point (AP) to a neighboring Access
Point (AP) provided that the station (STA) 136 is an authorized subscriber to
the
network. Similar to Wireless LAN (WLAN), there are also small-scale networks,
such
as Wireless Personal Area Network (WPAN), HomeRF, and Bluetooth networks, that
service small and mainly indoor coverage areas. The WPAN stations (STA) 134
are
usually small power handheld or indoor devices, such as Personal Digital
Assistant
(PDA) devices. Each WPAN Access Point (AP) 316 can only service subscribers
within radium of 10's meters. Such services are ideal for indoor environments.
Usually inter-network handoff and global roaming are not supported by WLAN
and WPAN. The systems are LAN based design for data services, no Public
Switched Telephone Network (PSTN) is connected to the system and no
Interworking Function (IWF) mechanism is built into these systems to support
cellular-quality voice call services, only Voice-Over-IP (VoIP) types of
applications
may be available. Although both WLAN and WPAN networks shares many
CA 02320573 2000-09-25
similarities, neither stations or Access Points are interoperable and inter-
service
handoff cannot be supported.
Reference is now made to Figure 3 wherein there is shown an architectural
diagram of a typical Universal Telecommunication System (UTS) 210, according
to
the invention, that provides broadband wireline and wireless services. The UTS
includes a plurality of interconnected Core Network Centers (CNCs) 200 that
support
circuit switched and packet switched services. The circuit switched domain
connects
to Public Switched Telephone Network (PSTN) and Integrated Services Digital
Network (ISDN), and the packet switched domain provides accesses to Internet
Protocol (IP), X.25, and other data networks. Although only one Core Network
Center
(CNC) 200 is shown in the drawing, it will be understood that it is for
illustration
purposes only. Each CNC 200 is further connected to a plurality of Universal
Access
Nodes (UANs) 100 through a regional broadband access network. A UAN can
perform the functions of Network Termination (NT) and Interworking Function
(IWF)
that can provide wireline 206 and wireless 205 service accesses from plurality
of
voice and data devices, namely cellular mobile stations (MS) 135, wireless
local area
network (WLAN) stations (STA) 136, wireless personal area network (WPAN)
devices such as personal digital assistants (PDA) 134, plain old telephone
service
(POTS) telephones 132, a life-line analog POTS device 131, local area network
(LAN) devices 133, printers, fax machines, other multimedia devices (not shown
in
the figure), and etc. Although only one Universal Access Node (UAN) 100 and a
few
different subscriber devices are shown, it will be understood that it is for
illustration
purposes only. Between UAN 100 and CNC 200, there is a regional broadband
access network connected UAN 100 to CNC 200, the connection 203 could be fiber
optic cables, copper cables (such as Digital Subscriber Line, or CATV cable),
or
Wireless Local Loop (WLL) radio links. The UAN 100 can also support high speed
accesses 204 to other networks (such as Community Antenna Television Network)
to
achieve access bandwidth sharing among different type of services and
different
networks.
There are different types of cellular technologies and services that can be
supported by UTS 210, such as Code Division Multiple Access (CDMA), Global
System for Mobile Communications (GSM), and Time Division Multiple Access
(TDMA). The CDMA types of technologies include the Second Generation (2G)
standards such as IS-95 and the Third Generation (3G) standards such as
European
Universal Mobile Telecommunication System (UMTS) in Europe, and CDMA 2000 in
North America. For cellular type of applications, the UAN 100 functions as a
base
transceiver station (BTS), the CNC 200 functions like a mobile switching
center
16
CA 02320573 2000-09-25
(MSC). For Wireless Local Area Network (WLAN) and Wireless Personal Area
Network (WPAN) types of applications, UAN 100 services as an access point (AP)
that connects a plurality of WLAN and WPAN stations (STAs). A station (STA)
can be
authenticated by the CNC 200 to support global roaming service, and the UAN
100
can be dynamically configured by the CNC 200 to support STA voice call
services as
well as inter-cell handoff services. For indoor voice and data applications, a
UAN
works like a combination of different high speed modems that can be configured
by
the CNC 200, the UAN 100 can translate the traffic data and send it to
different
Access Networks, and the CNC 200 is responsible to recover the signals and
connect them to different backbone networks.
In more detail, the Universal Access Node (UAN) 100 functional blocks and
interfaces illustrated in Figure 4 are as follows. There are a few high-speed
network
access interfaces available in the UAN, they allow UAN to connect to broadband
network infrastructure. Interface 112 is an interface to different flavors of
Digital
Subscriber Lines (xDSL), namely Asymmetric Digital Subscriber Line (ADSL,
6.992.1
or 6.992.2), High-Bit-Rate Digital Subscriber Line (HDSL or HDSL2), Symmetric
Digital Subscriber Line (SDSL or SDSL2), ISDN Digital Subscriber Line (IDSL),
Rate-
Adaptive Digital Subscriber Line (RADSL), and Very-High-Data-Rate Digital
Subscriber Line (VDSL). Interface 113 is an interface to high-speed cable
networks,
such as Community Antenna Television (CATV) network. Interface 111 is an
optical
interface that connects to broadband optical networks, such as Fiber-To-The-
Home
(FTTH), and Fiber-To-The-Building (FTTB). Interface 114 is an interface to
Wireless
Local Loop (WLL), also known as fixed wireless, such as Local Multipoint
Distribution
Services (LMDS) and Multichannel Multipoint Distribution Services (MMDS). The
interface 114 is connected to the RF/Microwave Front-End Module 116 for
RF/Microwave signals conversion. Interface 115 is an interface to Low-Earth
Orbiting
satellite (LEOs) and Middle-Earth Orbiting satellite (MEOs) networks. The
interface
115 is connected to the RF/Microwave Front-End Module 117 for RF/Microwave
signals conversion. Interface 123 is multiple LAN interfaces, such as 10 Base-
T
Ethernet connections. There are also multiple user interfaces, such as Plain
Old
Telephone Service (POTS) phones 124, a life-line analog POTS (0-4KHz)
connection
122, fax machines 125, and Universal Series Bus (USB) and other interfaces
126.
Each UAN can also have wireless interfaces, Radio Frequency Module (RFM) 102
and antenna 101 provides indoor and outdoor wireless accesses, namely
cellular,
personal Communication Services (PCS), and Wireless LAN. Due to small cell
site
coverage area, the maximum transmitted power for each service is usually
within a
few Watts. The RFM 102 converts RF signals to baseband signals 103 that can be
17
CA 02320573 2000-09-25
processed by Baseband Module 104, and vice versa. In some UAN design, Global
Positioning System Receiver (GPSR) 105 and GPS antenna 107 are required for
precise time-of-date reference in synchronous cellular systems, such as in
CDMA
systems. The GPSR 105 can provide reference clocks 106 to the Baseband Module
104. The UAN 100 can also provide wireless accesses for low power devices via
Radio Frequency Module (RFM) 127 and antenna 121, RFM 127 and antenna 121
are physically very small devices, especially with the state-of-art System-On-
Chip
(SOC) technologies. The RFM 127 can provide Wireless Personal Area Network
(WPAN), Bluetooth, HomeRF, and other similar technology low power (small
coverage area) accesses, and the maximum transmitted power for each service is
usually within 100's mW, ideal for indoor environments.
A typical embodiment of Universal Telecommunication System (UTS) based
on analog local loops is shown in Figure 5, illustrated generally at 130,
where the
high-speed links between a Core Network Center (CNC) 200 and the Universal
Access Nodes (UANs) 100 are generic Digital Subscriber Lines (xDSL) 112. The
network control signaling can be sent back and forward through the xDSL lines.
The
Digital Subscriber Line Access Multiplexer (DSLAM) 201 usually sits inside the
CNC
200. However, the DSLAM 201 could also be a remote DSLAM located out side of
CNC 200, the broadband link 202 between the DSLAM 201 and the CNC 200 could
be an optical, copper, or even radio link. The RF Module 102 and the Baseband
Module 104 illustrated generally at 100 are separate units, but they can also
be
integrated into one UAN box.
In a typical configuration, the UAN 100 is also connected to a CATV network
via coaxial cable 113. If the CATV network, like most of the CATV networks
nowadays, can only support high-speed data services. The Universal
Telecommunication System (UTS) service provider can lease a group of CATV
network internal Internet Protocol (IP) addresses from CATV service provider,
use
these IP addresses for high-speed data services for wireline and wireless
devices.
When the traffic on xDSL is approaching the maximum bandwidth, the CNC 200 may
dynamically assign these IP address to additional wireline and wireless data
devices
through UAN 100, so that the additional data traffic from these devices can be
routed
to CATV network. The same principle may also be applied to other networks,
such as
Local Multipoint Distribution Services (LMDS) and Multichannel Multipoint
Distribution
Services (MMDS), the additional traffic can be routed to MMDS and LMDS.
Figure 6 shows the embodiment of UTS based on CATV network, illustrated
generally at 140, where the broadband network between a Core Network Center
(CNC) 200 and the Universal Access Nodes (UANs) 100 is usually a Hybrid Fiber
18
CA 02320573 2000-09-25
Coaxial (HFC) network, such as Fiber To The Neighborhood (FTTN). Each CNC 200
is connected to multiple Optical Network Units (ONU) 211 through broadband
optical
network, and each ONU 211 can connect to multiple coaxial cables in the
neighborhood, and the coaxial cables 113 are finally distributed to the end
users.
Therefore a UAN 100 can communicate with the CNC 200 through the coaxial cable
connection 113. In the CATV network bandwidth allocation, voice traffic should
have
higher priority than data traffic, so that the delay of voice packets and
network control
messaging are guaranteed to be less than an acceptable level, regardless the
amount of data traffic. The CATV bandwidth planning has to guarantee enough
aggregate voice uplink and downlink bandwidth for voice services. The UAN can
also
be connected to an xDSL line 112 in order to route some voice and data packets
to
another broadband network to mitigate potential CATV network traffic
congestions.
The same principle may also be applied to other networks, such as Local
Multipoint
Distribution Services (LMDS) and Multichannel Multipoint Distribution Services
(MMDS), the additional traffic can be routed to MMDS and LMDS.
Figure 7 shows the embodiment of UTS based on Fiber To The Home (FTTH)
network, illustrated generally at 150, where the broadband network between a
Core
Network Center (CNC) 200 and the Universal Access Nodes (UANs) 100 is usually
a
Fiber-To-The-Home (FTTH) network. Each CNC 200 is connected to multiple
Optical
Add-Drop Multiplexers (OADM) 221 through the SONET ring 222, and each OADM
221 can connect to multiple UANs through fiber connections. Therefore a UAN
100
can communicate with the CNC 200 through a fiber connection 111. The optical
network usually has a very large bandwidth, with a single fiber connection,
the UAN
100 should have enough network access bandwidth for wireline and wireless.
Figure 8 shows the embodiment of UTS based on Wireless Local Loop (WLL)
networks, illustrated generally at 160, where the broadband network between a
Core
Network Center (CNC) 200 and the Universal Access Nodes (UANs) 100 is usually
a
WLL network. Such WLL network could be a Local Multipoint Distribution
Services
(LMDS) or a Multichannel Multipoint Distribution Services (MMDS) network. Each
CNC 200 is connected to multiple LMDS or MMDS transmission towers 231 through
optical or cable connections 212, and each LMDS/MMDS transmission tower 221
can connect to multiple UANs through air interface 232. Therefore a UAN 100
can
communicate with the CNC 200 through air interface 232. The UAN 100 can take
advantage of the WLL broadband access to provide wireline and wireless
services. If
the connections to other networks are available to the UAN 100, such as cable
network (not shown in Figure 8), they may help to mitigate the traffic
congestions.
19
CA 02320573 2000-09-25
Figure 9 shows the embodiment of UTS based on satellite networks,
illustrated generally at 170, where the broadband network between a Core
Network
Center (CNC) 200 and the Universal Access Nodes (UANs) 100 is a satellite
network. Such broadband access network could be a Low-Earth Orbiting (LEO) or
Middle-Earth Orbiting (MEO) satellite network. Each CNC 200 is connected to
the
satellite network through air interface, and each UAN is also connected to the
satellite network through air interface. Therefore a UAN 100 can communicate
with
the CNC 200 through the satellite network. The UAN 100 can take advantage of
the
broadband access satellite network to provide both wireline and wireless
services. If
the connections to other networks are available to the UAN 100, such as xDSL
and
CATV cable (not shown in Figure 8), they may help to mitigate the traffic
congestions. The embodiment of UTS differs from previous systems largely by
the
fact that the satellite network connected to a base station not a satellite
mobile
station, and the base station UAN can further service a plurality of devices
with
different air and wire interfaces. For a satellite mobile station, the mobile
communicates with satellites directly, and the call is constantly handed off
from one
satellite to another satellite even the mobile is stationary. Large power
consumption
is required fro the mobile due to long distance transmission between the
mobile and
the satellites, and some restrictions to the mobile such as line-of-sight may
be
applied. The embodiment of the UTS is not restricted to only metropolitan
areas, the
UAN can be installed to anywhere as long as line-of-sight is not a
restriction, such as
automobiles, public transportation, ships, airplanes, beach areas, and etc.
A Universal Access Network (UAN) 100(1) can be configured to Handover
mode, illustrated in Figure 10. Before a UAN enter a Handover mode, the UAN is
usually required to handover all the outdoor wireless services to the adjacent
cells. In
Handover mode, a UAN 100(1 ) no longer serves as a wireless access node, the
UAN
100(1) stop transmitting pilot channel or beacon, the cell site service is
shut down.
The mobile stations (MS) in the area cannot detect this cell, they can only
access to
other adjacent cells. However, in Handover mode, a UAN 100(1 ) may still
communicate with one of the neighboring UAN's 100(2) like a normal mobile
station.
The Handover mode can be achieved in both cellular and Wireless LAN (WLAN)
solutions. In cellular systems, the CNC 200 can first send a "start handover"
signal to
UAN 100(1) through UAN 100(2) downlink 207(2), once UAN 100(1) receives the
signal, UAN 100(1) send the response messages to CNC 200 through UAN 100(2)
uplink 207(1). Once the communication links between CNC 200 and UAN 100(1)
through UAN(2) are established, the UAN 100(1 ) can direct partial or all of
the traffic
from its wireline and indoor Wireless Personal Area Network (WPAN) services to
the
CA 02320573 2000-09-25
adjacent UAN 100(2), then from UAN 100(2) to CNC 200 via high-speed link
112(2).
The UAN 100(1) successfully enters Handover mode. In WLAN systems, the CNC
200 can first send a "start handover" signal to UAN 100(1) through UAN 100(2)
access frequency 207(2), once UAN 100(1) receives the signal, UAN 100(1) send
the
response messages to CNC 200 through UAN 100(2) access frequency 207(1).
Once the communication links between CNC 200 and UAN 100(1 ) through UAN(2)
are established, the UAN 100(1 ) can direct partial or all of the traffic from
its wireline
and indoor Wireless Personal Area Network (WPAN) services to the adjacent UAN
100(2), then from UAN 100(2) to CNC 200 via high-speed link 112(2). The UAN
100(1 ) successfully enters Handover mode. Once UAN 100(1 ) is in Handover
mode,
it also means traffic handover from UAN 100(2) to UAN 100(1 ), it also allows
UAN
100(2) to direct its traffic to UAN 100(1), and utilize 112(1) high-speed link
to carry
UAN 100(2) traffic.
The Handover mode is very important for xDSL type of high-speed link
connection. Once the UAN 100(1 ) and CNC 200 start to communicate with the
established links, the high-speed can be shut down for retraining. All the
voice call
services are not interrupted. The Handover mode is also a way to take
advantage of
the unutilized bandwidth in the adjacent cells to provide higher bandwidth
wireline
services.
A Universal Access Network (UAN) 100(2) can be configured to Relay mode,
illustrated in Figure 11. Before a UAN enter a Relay mode, the UAN is usually
required to handover all the outdoor wireless services to the adjacent cells.
In Relay
mode, a UAN 100(1) no longer serves as a wireless access node, the UAN 100(1)
stop transmitting pilot channel or beacon, the cell site service is shut down.
The
mobile stations (MS) in the area cannot detect this cell, they can only access
to other
adjacent cells. However, in Relay one mode, the UAN 100(2) can communicate
with
two of its neighboring UANs 100(1) and 100(3) at the same time. The Relay mode
is
mainly used in Wireless LAN (WLAN) solutions. In WLAN systems, the CNC 200 can
configure UAN 100(2) to communicate with UAN 100(1) like a WLAN station (STA)
at
the same frequency 207(1) of UAN 100(1), at the same time, CNC 200 also
configure
UAN 100(2) to communicate with UAN 100(3) like a WLAN station (STA) at the
same
frequency 207(2) of UAN 100(3). Once the communication links are established,
the
traffic between CNC 200 and UAN 100(1) can be routed from CNC 200 to UAN
100(3) via 203(3), then from UAN 100(3) to UAN 100(2) via 207(2), then from
UAN
100(2) to UAN (1) via 207(1). Once a UAN 100(2) is in Relay mode for UAN
100(1)
and UAN 100(3), it automatically in handover mode with UAN 100(1) and UAN
100(3).
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CA 02320573 2000-09-25
In some application scenarios where the short-time bandwidth demand from
subscribers exceeds the maximum bandwidth of the high-speed link, the
bandwidth
problem can be mitigated by setting some of the adjacent UANs to Handover mode
or Relay mode, illustrated in Figure 11. The UAN 100(1) can achieve extra
network
access bandwidth through high-speed link 203(4) via UAN 100(4) that is in
Handover
mode. The UAN 100(1) can also gain extra network access bandwidth through
203(2) and 203(3) via UAN 100(2) and UAN 100(3) by setting UAN 100(2) to Relay
mode.
Relay mode is very useful feature for the network to offer such as Video-On-
Demand
(VOD) and Music-On-Demand (MOD) types of broadband services.
Global roaming and voice call services can be offered to Wireless LAN station
136, shown in Figure 12. The wireless LAN station (STA) 136 is capable of
global
roaming with or without a permanent IP address. Each wireless LAN station
(STA)
136 is assigned a unique STA global ID and a directory number (DN) just like a
mobile ID and a directory number for a cellular phone, the global ID could be
simply
an International Mobile Station Identity (IMSI) defined by the International
Telecommunication Union (ITU). The network maintains association between the
mobile's ID and its directory number. Therefore a wireless LAN system and a
cellular
system can share the existing cellular network database. During the
authentication in
a visitor location, the MS identifies its global ID to the visited Core
Network Center
(CNC) 200. According to the global ID, visited CNC 200 can query the STA Home
Location Register (HLR) 401 database to obtain the STA profile. The HLR is a
database entity in which the main database entry of a STA resides. The HLR
contains the STA's profile, STA user interface information, current status,
and
location information. From the STA's profile, the visited CNC 200 obtains the
Shared
Secret Key and sends it to the universal access node (UAN) 100(1 ) which
function as
an access point (AP) 100(1 ) in the wireless LAN system. The AP 100(1 )
continues to
perform Shared Key authentication with wire equivalent privacy (WEP)
encryption or
a proprietary encryption. The Shared Secret Key is unique and only known by
the
STA 136 and AP 100(1). Once the STA 136 is successfully authenticated, the HLR
401 and Visitor Location Register (VLR) 402 entries will be updated to
indicate where
the STA 136 is being services. The HLR 401 and VLR 402 are usually required
for
some of the IS-41 operations. The HLR 401 and VLR 402 together govern the
location and status of the STA 136. When a STA moves from one CNC to another
CNC, the VLR keeps track of the STA by gathering information from the HLR
through
STA association. If the STA 136 does not have a permanent IP address
registered in
the HLR 401 profile, the visited CNC 200 can assign a dynamic IP address to
the
22
CA 02320573 2000-09-25
STA 136. If the STA 136 has a permanent address registered in the HLR 401
profile,
the STA 136 may be given a choice of using its permanent address or a dynamic
address. If the STA 136 chooses to use its permanent address, the STA 136
incoming data traffic will be routed to the home CNC (not shown) first, and
then
redirected to the visited CNC 200, the out going traffic is not necessary to
be routed
to the home CNC (not shown). After the STA 136 is associated with the AP 100(1
),
the STA 136 is able to provide a regular voice call services. A Virtual
Channel
Connection (VCC) can be set up between the STA 136 and the CNC 200, from the
CNC 200, it connects to the public switched telephone network (PSTN). The STA
136 can be configured with different Vocoder schemes dependent on the services
availability.
Figure 12 illustrates the inter-cell handover between two UANs 100(1) and
100(2) in Wireless LAN applications. The Wireless LAN station (STA) 136 is
moving
from UAN 100(1) coverage area to UAN 100(2) coverage area. The STA 136 is
handed over from UAN 100(1 ) to UAN 100(2).
The detail procedure can be referenced in Figure 13:
1) The data transmission between STA 136 and CNC 200 is via UAN1
100(1) at cell-site frequency Freq1
2) UAN2 100(2) uses the second channel to tune to the neighboring UANs
and measure the transmission powers from stations serviced by the
neighboring cells periodically, such as the transmission power from STA
136
3) UAN2 100(2) reports the measured results to CNC 200
4) CNC 200 decides if the STA 136 should be handed over to a neighboring
UAN2 100(2) based on the power measurements from the UANs in the
neighborhood and the traffic conditions in each of the cells. Once the
decision is made, CNC 200 sends the information of STA 136 and a
Handover Request message to UAN2 100(2), The STA information may
include the Shared Secret Key, Initialization Vector, or other proprietary
security keys, and etc.
5) UAN2 100(2) uses the second channel to send the Handover Request
message to STA 136 like a normal station in UAN1 100(1) cell. The
Request message includes UAN2 100(2) Cell-Site information.
6) STA 136 send a Handover Request Acknowledge message back to CNC
200 through UAN2 100(2) at Freq1.
7) STA 136 begins to communicate with CNC 200 through UAN2 100(2) at
Freq 1
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CA 02320573 2000-09-25
8) STA 136 continues receiving queued packets from UAN1 100(1)
9) CNC 200 sends a Handover Ready to UAN1 100(1) to indicate that STA
136 is about to be handed over to another UAN
10) After finishing sending all the queued packets for STA 136, UAN1 100(1)
sends a Handover Ready Acknowledge message back to CNC 200
11 ) CNC 200 sends a Start Handover Process command to STA 136 through
UAN2 100(2) at Freq1
12) STA 136 starts to listen to UAN2 100(2) cell-site Beacon signal at Freq2,
and send the Handover Process Complete message back to CNC 200
through UAN2 100(2) at Freq2.
13) STA 136 starts to communicate with CNC 200 through UAN2 100(2) cell-
site services at Freq2
Figure 14 illustrates the inter-system handover between two CNCs 200(1)
and 200(2) in Wireless LAN applications. The Wireless LAN station (STA) 136 is
moving from CNC 200(1 ) coverage area UAN 100(1 ) to CNC 200(2) coverage area
UAN 100(2). The STA 136 is handed over from UAN 100(1 ) to UAN 100(2).
The detail procedure can be referenced in Figure 15:
1) The data transmission between STA 136 and CNC1 200(1) is via UAN1
100(1) at cell-site frequency Freq1
2) UAN2 100(2) uses its second channel to tune to the neighboring UANs
and measure the transmission powers from stations serviced by the
neighboring cells periodically, such as the transmission power from STA
136, UAN2 100(2) reports the measured results to CNC2 200(2)
3) CNC2 200(2) reports the measured results to CNC1 200(1)
4) CNC1 200(1) decides if the STA 136 should be handed over to a
neighboring UAN2 100(2) based on the power measurements from the
UANs in the neighborhood and the traffic conditions in each of the cells.
Once the decision is made, CNC1 200(1) sends the profile information of
STA 136 and a Handover Request message to CNC2 200(2)
5) CNC2 200(2) sends a Handover Request message to UAN2 100(2) with
STA information, such as the Shared Secret Key, Initialization Vector, or
other proprietary security keys, and etc.
6) UAN2 100(2) uses the second channel to send the Handover Request
message to STA 136 like a normal station in UAN1 100(1) cell. The
Request message includes UAN2 100(2) Cell-Site information.
7) STA 136 send a Handover Request Acknowledge message back to
CNC2 200(2) through UAN2 100(2) at Freq1.
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8) CNC2 200(2) update the Visitor Location Register (VLR) database to
include the profile of STA 136, STA 136 begins to communicate with
CNC 200 through UAN2 100(2) at Freq1
9) STA 136 continues receiving queued packets from UAN1 100(1)
10) CNC2 200(2) sends a Handover Ready to CNC1 200(1 ), and CNC1
200(1) pass the message to UAN1 100(1) to indicate that STA 136 is
about to be handed over to another UAN
11 ) After finishing sending all the queued packets for STA 136, UAN 1 100(1 )
sends a Handover Ready Acknowledge message back to CNC1 200(1),
and CNC1 200(1) passes the message to CNC2 200(2)
12) CNC2 200(2) sends a Start Handover Process command to STA 136
through UAN2 100(2) at Freq1
13) STA 136 starts to listen to UAN2 100(2) cell-site Beacon signal at Freq2,
and send the Handover Process Complete message back to CNC2
200(2) through UAN2 100(2) at Freq2.
14) STA 136 starts to communicate with CNC2 200(2) through UAN2 100(2)
cell-site services at Freq2
Figure 16 shows the co-existing of Universal Access Nodes (UAN) and
conventional Base Transceiver Stations (BTS) in the cellular systems. A UAN
can be
deployed just like a regular BTS, illustrated generally at 411. The little
differences
between BTS 312(1) and UAN 100(6) functionally, except the fact that BTS
312(1) is
connected to dedicated T1/E1 links 314 to a Base Station Controller (BSC) 317,
the
links between BSC 317 and CNC 200(1) are also dedicated E1/T1 lines, however
UAN 100(6) is simply connected to a high-speed link such as xDSL, the
different
types of high-speed links require different line interfaces at the CNC 100(1 )
and MSC
313(1). The MSC 313(1) and CNC 200(1) can be located in the same central
office.
The mobile station (MS) 135(1) can operate in the UAN 100(6) coverage area,
perform soft and hard hand-offs between BTS 312(1 ) and UAN 100(6) just like
it is in
a regular MSC network. Once MS 135(1) is in UAN 100(6) coverage area, the
distance the MS 135(1) is away from the UAN 100(6) can be roughly determined
by
various algorithms depended on the cellular technology. The UAN 100(6) may be
informed the possible cheaper Wireless LAN (WLAN) or Wireless Personal Area
Network (WPAN) services once available, and the information of the Access
Points
(AP) available in the area. If MS 135(1) is also capable of working in WLAN or
WPAN
mode, it can be handed over to the WLAN or WPAN services. The Inter-Service
handover feature can be supported by the CNC 200(1 ). The boundary UAN also
CA 02320573 2000-09-25
warns the mobile that the serving cell is a boundary or stand-alone cell, the
services
may not be available while leaving the area.
As illustrated generally at 412, a Master Universal Access Node (UAN) or
Base Transceiver Station (BTS) 312(2) cover the area where the Slave UAN
100(1),
Slave UAN 100(2), and Slave UAN 100(3) are located. When there is no mobile in
the Slave UAN 100(2) coverage area, the Slave UAN 100(2) can be put in Sleep
mode, it shuts down its cell site service to reduce interference to other
UANs, and
continues to listen to the reverse links of the Master UAN 312(2) and
neighboring
serving Slave UANs 100(1). The signal quality of the reverse links is measured
and
reported to CNC 200(2). When a mobile station is nearby, the reverse link
signal to
its serving UAN becomes strong. The CNC 200(2) may wake up the UAN 100(2)
from Sleep mode to commence cell site service. For Universal Mobile
Telecommunication System (UMTS) type of systems, the Master UAN and the Slave
UANs can operate at the same frequency. For a synchronous system, such as
North
American Code Division Multiple Access (CDMA) systems, the Master UAN or BTS
312(2) may operate at one forward link frequency Freq1 and the rest of Slave
UANs
100(1-3) may operate at a different forward link frequency Freq2. The Slave
UANs
can listen to the Master at Freq1 periodically for timing information in order
to
synchronize their clocks, all the delay factors were considered and pre-
calibrated at
beginning of the system deployment. When the Slave UAN 100(2) is in Sleep
mode,
it listens to the reverse link of the Master BTS 312(2) and the reverse link
of the
neighboring serving Slave UANs 100(1 ) periodically. Note that the Master and
Slave
reverse links may be at different frequencies. The signal quality of the
reverse links is
measured and reported to CNC 200(2). The CNC 200(2) may wake up the UAN
100(2) from Sleep mode to commence cell site service. Therefore, a Slave UAN
does
not need a Global Positioning System Receiver (GPSR) in the UAN design. The
Master UAN 312(2), like the conventional base stations today, is mainly
responsible
for large coverage area to ensure service continuity, once a mobile station
enters the
metropolitan area where the Universal Telecommunication System (UTS) services
are available, it may be handed off to a Slave UAN, the Slave UANs 100(1-3)
are
responsible for high-density subscriber services, such as in urban areas. The
MSC
313(2) and CNC 200(1 ) can be located in the same central office.
As illustrated generally at 413, two or more UANs 100(4-5) can be configured
as a single cell to offer space diversity and frequency diversity to the
mobile stations
(MS) 135(3).
When a MS 135(2) is turned on to register the service from CNC 200(2), all
the voice mail recorded at the home Voice Mail System (VMS) 404 can be
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automatically compresses and downloaded to the MS 135(2) as data packets via
the
local CNC 200(2). The mobile can decompress and listen to messages without
dialing a number to the voice message center.
Figure 17 summarizes the different Slave Universal Access Node (SUAN)
modes that are available in mobile telecommunication systems. If the SUAN is a
synchronous UAN, it has to listen to a Master UAN (MUAN) forward link for
timing
information periodically to synchronize it own internal clock. Operation mode
is the
normal operating mode in which the SUAN provide full cell site services to its
mobile
stations (MS). In Sleep mode, the SUAN shuts down its cell-site services to
save
power and reduce inter-cell interference, the SUAN can no longer be detected
by a
mobile station (MS). While in Handover mode, the SUAN first shuts down its
cell-site
services, then communicates with a neighboring UAN like a mobile station (MS)
being serviced by the neighboring UAN. In Handover mode, some of the SUAN
traffic
can be routed to the neighboring UAN, and vice versa.
Figure 18 summarizes the different Universal Access Node (UAN) modes that
are available in Wireless LAN (WLAN) systems. Each UAN has two independent
frequency channels. In Operation mode, one channel provides full cell site
services
to its WLAN stations (STA), the other channel can be tuned to a Neighboring
UAN
frequency from time to time to measure the STA power. In Sleep mode, the UAN
shuts down its cell-site services to save power and reduce inter-cell
interference, the
UAN can no longer be detected as an Access Point (AP) by a station (STA), both
channels are listening to neighboring UANs. While in Handover mode, the SUAN
uses its second channel to communicate with a neighboring UAN like a normal
station (STA) being serviced by the neighboring UAN. In Handover mode, some of
the UAN traffic can be routed to the neighboring UAN, and vice versa. Finally
there is
Relay mode, in which both channels are used to communicate with two
neighboring
UANs, the said UAN no longer provides cell-site services.
Examples have been shown to demonstrate various aspects of the invention,
but the number of variations is by no means complete. Comparable
implementations
could be made for many telephony devices, including personal digital
assistants, fax
machines, pagers, point of sale computers, amateur radios, local area networks
or
private branch exchanges. While particular embodiments of the present
invention
have been shown and described, it is clear that changes and modifications may
be
made to such embodiments without departing from the true scope and spirit of
the
invention.
The method steps of the invention may be embodied in sets of executable
machine code stored in a variety of formats such as object code or source
code.
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Such code is described generically herein as programming code, or a computer
program for simplification. Clearly, the executable machine code may be
integrated
with the code of other programs, implemented as subroutines, by external
program
calls or by other techniques as known in the art.
The embodiments of the invention may be executed by a computer processor
or similar device programmed in the manner of method steps, or may be executed
by
an electronic system which is provided with means for executing these steps.
Similarly, an electronic memory means such computer diskettes, CD-Roms, Random
Access Memory (RAM), Read Only Memory (ROM) or similar computer software
storage media known in the art, may be programmed to execute such method
steps.
As well, electronic signals representing these method steps may also be
transmitted
via a communication network.
It would also be clear to one skilled in the art that the principles of the
invention could be applied to many other ways without taking away from the
invention.
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