U.S. patent application number 11/110222 was filed with the patent office on 2011-06-23 for method and system for signaling traffic and media types within a communications network switching system.
Invention is credited to Michael D. Gallagher, Puneet Goel, Milan Markovic.
Application Number | 20110149838 11/110222 |
Document ID | / |
Family ID | 44070915 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110149838 |
Kind Code |
A1 |
Gallagher; Michael D. ; et
al. |
June 23, 2011 |
METHOD AND SYSTEM FOR SIGNALING TRAFFIC AND MEDIA TYPES WITHIN A
COMMUNICATIONS NETWORK SWITCHING SYSTEM
Abstract
Signaling regarding traffic and media types within a
communications network control system is described. In one
embodiment, the invention includes receiving an assignment request
message from a call server of a communications network, the
assignment request message including a description of a bearer
connection between a subscriber and the communications network,
sending a channel activation request to the subscriber, the channel
activation request including at least a portion of the description
of the bearer connection between the subscriber and the
communications network, receiving connection information about a
channel activated by the subscriber in response to the channel
activation request, and sending the connection information to the
call server to allow the call server to modify the bearer
connection.
Inventors: |
Gallagher; Michael D.; (San
Jose, CA) ; Goel; Puneet; (Mountain View, CA)
; Markovic; Milan; (Pleasanton, CA) |
Family ID: |
44070915 |
Appl. No.: |
11/110222 |
Filed: |
April 20, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11013883 |
Dec 15, 2004 |
7640008 |
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11110222 |
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10688470 |
Oct 17, 2003 |
7127250 |
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11013883 |
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60564566 |
Apr 21, 2004 |
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60651312 |
Feb 9, 2005 |
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Current U.S.
Class: |
370/328 ;
370/352 |
Current CPC
Class: |
H04W 76/22 20180201;
H04W 36/0066 20130101; H04W 84/045 20130101 |
Class at
Publication: |
370/328 ;
370/352 |
International
Class: |
H04W 4/00 20090101
H04W004/00; H04L 12/66 20060101 H04L012/66 |
Claims
1-27. (canceled)
28. A method comprising: receiving, at a network controller of a
first communication network that communicatively couples at least
one service region of the first communication network to a licensed
wireless second communication network, a description of a bearer
connection from a call server of the second communications network,
the bearer connection to be established between the second
communications network and a subscriber device; sending the
description of the bearer connection from the network controller to
the subscriber device to allow the subscriber device to establish
the bearer connection through the network controller to the second
communications network; receiving, at the network controller,
connection information about the established bearer connection from
the subscriber device; sending the connection information from the
network controller to the call server to allow the call server to
modify the bearer connection; before the bearer connection is
modified by the call server, forwarding RTP packets in only one
direction at the network controller from the subscriber device to a
media gateway of the second communications network; and after the
bearer connection is modified by the call server, forwarding RTP
packets at the network controller (i) from the subscriber device to
the media gateway and (ii) from the media gateway to the subscriber
device.
29. The method of claim 28, wherein the bearer connection is a VoIP
connection.
30. The method of claim 28, wherein the description of the bearer
connection comprises an RTP port number and an IP address of a
media gateway of the second communications network.
31. The method of claim 30, wherein the connection information
about the established bearer connection comprises an RTP port
number and an IP address of the subscriber device.
32-41. (canceled)
42. A method comprising: receiving, at a network controller of a
first communications network that communicatively couples at least
one service region of the first communications network to a
licensed wireless second communications network, a message from a
call server of the second communications network, the message
comprising a request for modification of an established bearer
connection between the second communications network and a
subscriber device through the network controller; sending a request
from the network controller to the subscriber device to modify the
bearer connection based on the message from the call server; and
when the subscriber device is able to modify the bearer connection,
passing traffic packets through the network controller between the
subscriber device and a mobile switching center (MSC) of the second
communications network over the modified bearer connection; and
when the subscriber device is unable to modify the bearer
connection, maintaining the bearer connection using an IP address
and an UDP port associated with the bearer connection.
43. The method of claim 42 further comprising sending an
acknowledgment from the subscriber device to the network controller
in response to the request to modify the bearer connection.
44. The method of claim 43, wherein the modification of the bearer
connection comprises applying RTP Redundancy.
45. The method of claim 44, wherein when the subscriber device is
unable to modify the bearer connection, the acknowledgment
comprises an indication that the subscriber device is unable to
handle the requested modification.
46. The method of claim 42, wherein modification of the established
bearer connection comprises modification to at least one of an IP
address and a UDP port associated with the bearer connection.
47. (canceled)
48. For a network controller of a first communication network that
communicatively couples at least one service region of the first
communication network to a licensed wireless second communication
network, a non-transitory computer readable medium storing a
computer program for execution by the network controller, the
computer program storing sets of instructions for: receiving a
message from a call server of the second communications network,
the message comprising a request for modification of an established
bearer connection between the second communications network and a
subscriber device through the network controller; sending a request
to the subscriber device to modify the bearer connection based on
the message from the call server; passing traffic packets through
the network controller between the subscriber device and a mobile
switching center (MSC) of the second communications network over
the modified bearer connection when the subscriber device is able
to modify the bearer connection; and clearing an ongoing call on
the established connection when the subscriber device is unable to
modify the bearer connection.
49-50. (canceled)
51. The non-transitory computer readable medium of claim 48,
wherein the computer program further comprises a set of
instructions for sending an acknowledgment from the subscriber
device to the network controller in response to the request to
modify the bearer connection.
52. The non-transitory computer readable medium of claim 51,
wherein when the subscriber device is unable to modify the bearer
connection, the acknowledgment comprises an indication that the
subscriber device is unable to handle the requested modification.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of provisional patent
application Ser. No. 60/564,566 filed Apr. 21, 2004 and entitled
"A+ Interface Specification" and provisional patent application
Ser. No. 60/651,312, filed Feb. 9, 2005, and entitled "An Improved
Unlicensed Mobile Access Network (UMAN) System and Method." This
application is a Continuation in Part of and claims the priority of
U.S. Nonprovisional application Ser. No. 11/013,883, entitled
"Apparatus and Method for Extending the Coverage Area of A Licensed
Wireless Communication System Using an Unlicensed Wireless
Communication System," filed Dec. 15, 2004, which is a Continuation
in Part of U.S. Nonprovisional application Ser. No. 10/688,470,
entitled "Apparatus and Method for Extending the Coverage Area of a
Licensed Wireless Communication System Using an Unlicensed Wireless
Communication System," filed Oct. 17, 2003.
[0002] This application is also related to commonly owned U.S.
Applications: Ser. No. 10/115,833, entitled "Unlicensed Wireless
Communications Base Station to Facilitate Unlicensed and Licensed
Wireless Communications with a Subscriber Device, and Method of
Operation," filed Apr. 2, 2002; and application Ser. No.
10/251,901, entitled "Apparatus for Supporting the Handover of a
Telecommunication Session between a Licensed Wireless System and an
Unlicensed Wireless System," filed Sep. 20, 2002, the contents of
each of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0003] The present description relates to communications with a
call server in a public land mobile network, and, in particular, to
communicating information about traffic formats and parameters with
a call server.
BACKGROUND INFORMATION
[0004] Licensed wireless systems provide mobile wireless
communications to individuals using wireless transceivers. Licensed
wireless systems refer to public cellular telephone systems and/or
Personal Communication Services (PCS) telephone systems. Wireless
transceivers include cellular telephones, PCS telephones,
wireless-enabled personal digital assistants, wireless modems, and
the like.
[0005] Licensed wireless systems utilize wireless signal
frequencies that are licensed from governments. Large fees are paid
for access to these frequencies. Expensive base station (BS)
equipment is used to support communications on licensed
frequencies. Base stations are typically installed approximately a
mile apart from one another (e.g., cellular towers in a cellular
network). The wireless transport mechanisms and frequencies
employed by typical licensed wireless systems limit both data
transfer rates and range. As a result, the quality of service
(voice quality and speed of data transfer) in licensed wireless
systems is considerably inferior to the quality of service afforded
by landline (wired) connections. Thus, the user of a licensed
wireless system pays relatively high fees for relatively low
quality service.
[0006] Landline (wired) connections are extensively deployed and
generally perform at a lower cost with higher quality voice and
higher speed data services. The problem with landline connections
is that they constrain the mobility of a user. Traditionally, a
physical connection to the landline was required.
[0007] In the past few years, the use of unlicensed wireless
communication systems to facilitate mobile access to landline-based
networks have seen rapid growth. For example, such unlicensed
wireless systems may support wireless communication based on the
IEEE 802.11a, b or g standards (WiFi), or the Bluetooth.TM.
standard. The mobility range associated with such systems is
typically on the order of 100 meters or less. A typical unlicensed
wireless communication system includes a base station comprising a
wireless access point (AP) with a physical connection (e.g.,
coaxial, twisted pair, or optical cable) to a landline-based
network. The AP has a RF (Radio Frequency) transceiver to
facilitate communication with a wireless handset that is operative
within a modest distance of the AP, wherein the data transport
rates supported by the WiFi and Bluetooth.TM. standards are much
higher than those supported by the aforementioned licensed wireless
systems. Thus, this option provides higher quality services at a
lower cost, but the services only extend a modest distance from the
base station.
[0008] Currently, technology is being developed to integrate the
use of licensed and unlicensed wireless systems in a seamless
fashion, thus enabling a user to access, via a single handset, an
unlicensed wireless system when within the range of such a system,
while accessing a licensed wireless system when out of range of the
unlicensed wireless system. In a conventional mobile communication
system, the coding and format for voice and data traffic has a
predetermined configuration. In order to communicate with equipment
within the mobile communication system, any voice or data traffic
must first be reconfigured to correspond to the predetermined
norms.
[0009] Some portions of a mobile communications system may have
transcoding equipment capable of changing voice or data encoding or
formatting. However, since the transcoding equipment is designed
only to work according to the predetermined norms, there may be no
provision for reconfiguring the equipment to transcode into or out
of other formats. In, for example, a GSM (Global System for Mobile
Communication) base station subsystem, specialized media gateways
(i.e., transcoder and rate adaptation units) are used to convert
voice traffic from the coding and format of the cellular telephone
to the PCM (Pulse Code Modulation) TDM (Time Division Multiplexed)
format of the land network. To support other types of codecs, for
example, those used in voice over IP, an additional TRAU is used to
convert traffic between native voice over IP formats and native GSM
formats. The additional components add complexity and expense to
the system.
SUMMARY OF THE INVENTION
[0010] Signaling regarding traffic and media types within a
communications network control system is described. In one
embodiment, the invention includes receiving an assignment request
message from a call server of a communications network, the
assignment request message including a description of a bearer
connection between a subscriber and the communications network,
sending a channel activation request to the subscriber, the channel
activation request including at least a portion of the description
of the bearer connection between the subscriber and the
communications network, receiving connection information about a
channel activated by the subscriber in response to the channel
activation request, and sending the connection information to the
call server to allow the call server to modify the bearer
connection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, wherein like reference numerals refer to like parts
throughout the various views unless otherwise specified:
[0012] FIG. 1A provides an overview of the indoor access network
(IAN) mobile service solution in accordance with one embodiment of
the present invention;
[0013] FIG. 1B illustrates protocol layers of a mobile set in
accordance with one embodiment;
[0014] FIG. 1C illustrates a method of protocol conversion in
accordance with one embodiment;
[0015] FIG. 2A illustrates an overview of a level 1, level 2, and
level 3 GSM-related protocol architecture for one embodiment of a
mobile station that provides unlicensed radio links via Bluetooth
signaling;
[0016] FIG. 2B illustrates an overview of a level 1, level 2, and
level 3 GSM-related protocol architecture for one embodiment of a
mobile station that provides unlicensed radio links via IEEE 802.11
signaling;
[0017] FIG. 3A illustrates the Up interface protocol architecture
in support of CS Domain signaling, as well as UMA-specific
signaling, according to one embodiment;
[0018] FIG. 3B shows Bluetooth lower layers employed by a mobile
station and access point to facilitate physical layer
communications;
[0019] FIG. 3C shows Bluetooth lower layers employed by a mobile
station and access point to facilitate physical layer
communications;
[0020] FIG. 3D illustrates the Up CS domain voice bearer protocol
architecture in support of GSM voice transmission, according to one
embodiment;
[0021] FIG. 3E illustrates the Up GPRS user plane protocol
architecture, according to one embodiment;
[0022] FIG. 5 illustrates an enhanced UMA architecture in one
embodiment also without packet data elements;
[0023] FIG. 6A illustrates an enhanced Up interface protocol
architecture in support of CS Domain signaling, as well as UMA
specific signaling in accordance with one embodiment;
[0024] FIG. 6B illustrates an enhanced Up Audio interface protocol
architecture with direct passage of higher layers to a media
gateway, according to one embodiment;
[0025] FIG. 7 is a message and data flow diagram illustrating
messages and operations employed to establish a connection between
a mobile station and a MSC Call Server, according to one
embodiment;
[0026] FIG. 8 is a message and data flow diagram illustrating
messages and operations employed to handover a call from a licensed
base station to a mobile wireless LAN according to an
embodiment;
[0027] FIG. 9 is a message and data flow diagram illustrating
messages and operations employed to modify a bearer connection
according to an embodiment; and
[0028] FIG. 10 is a message and data flow diagram illustrating
messages and operations employed to indicate uplink quality
according to an embodiment.
DETAILED DESCRIPTION
[0029] In the following description, numerous specific details are
set forth to provide a thorough understanding of embodiments of the
invention. One skilled in the relevant art will recognize, however,
that the invention can be practiced without one or more of the
specific details, or with other methods, components, materials,
etc. In other instances, well-known structures, materials, or
operations are not shown or described in detail to avoid obscuring
aspects of the invention.
[0030] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
the appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment. Furthermore, the
particular features, structures, or characteristics may be combined
in any suitable manner in one or more embodiments.
[0031] In the present description the unlicensed wireless system
may be a short-range wireless system, which may be described as an
"indoor" solution. However, it will be understood through the
application that the unlicensed wireless system includes unlicensed
wireless systems that cover not only a portion of a building but
also local outdoor regions, such as outdoor portions of a corporate
campus serviced by an unlicensed wireless system. The mobile
station may, for example, be a wireless phone, smart phone,
personal digital assistant, or mobile computer. The "mobile
station" may also, for example, be a fixed wireless device
providing a set of terminal adapter functions for connecting
Integrated Services Digital Network (ISDN) or Plain Old Telephone
Service (POTS) terminals to the wireless system. Application of the
present invention to this type of device enables the wireless
service provider to offer so-called landline replacement service to
users, even for user locations not sufficiently covered by the
licensed wireless system. The present description is in the context
of the UMA (Unlicensed Mobile Access) standardized architecture as
promulgated by the UMA consortium. However, the invention is not so
limited.
[0032] Throughout the following description, acronyms commonly used
in the telecommunications industry for wireless services are
utilized along with acronyms specific to the present invention. A
table of acronyms specific to this application is included in
Appendix I.
[0033] FIG. 1A illustrates an Unlicensed Mobile Access (UMA)
architecture 100 in accordance with one embodiment of the present
invention. UMA architecture 100 enables a user of a mobile station
102 to access a voice and telecommunications network 104 via either
a licensed wireless communications session 106, or an unlicensed
wireless communication session 108. The telecommunications network
104 includes a mobile switching center (MSC) 110, which provides
access to a voice network 112, and a Serving GPRS (General Packet
Radio Service) Support Node (SGSN) 114, which provides access to a
data network 116. MSC 110 also provides an internal visitor
location register (VLR) function.
[0034] In further detail, the licensed wireless communication
session is facilitated by infrastructure provided by a licensed
wireless network 118 that includes telecommunications network 104.
In the illustrated embodiment, licensed wireless network 118
depicts components common to a GSM-(Global System for Mobile
Communication) based cellular network that includes multiple base
transceiver stations (BTS) 120 (of which only one is shown for
simplicity) that facilitate wireless communication services for
various mobile stations 102 via respective licensed radio links 122
(e.g., radio links employing radio frequencies within a licensed
bandwidth). Typically, the multiple BTSs 120 are configured in a
cellular configuration (one per each cell) that covers a wide
service area. The various BTSs 120 for a given area or region are
managed by a base station controller (BSC) 124, with each BTS 120
communicatively-coupled to its BSC 124 via a private trunk 126. In
general, a large licensed wireless network, such as that provided
by a regional or nationwide mobile services provider, will include
multiple BSCs 124.
[0035] Each BSC 124 communicates with telecommunications network
104 through a standard base station controller interface 126. For
example, a BSC 124 may communicate with MSC 110 via the GSM
A-interface for circuit switched voice services and with SGSN 114
via the GSM Gb interface for packet data services (GPRS).
Conventional licensed voice and data networks 104 include protocols
to permit seamless handoffs from one recognized BSC 124 to another
BSC (not shown).
[0036] An unlicensed communication session 108 is facilitated via
an (wireless) access point (AP) 128 comprising an indoor base
station 130. Typically, AP 128 will be located in a fixed
structure, such as a home 132 or an office building 134. The
service area of indoor base station 130 includes an indoor portion
of a building, although it will be understood that the service area
of an indoor base station may include an outdoor portion of a
building or campus. As indicated by the arrow representing
unlicensed communication session 108, the mobile station 102 may be
connected to the telecommunications network 114 via a second data
path that includes an unlicensed wireless channel 136, access point
128, an access network 138, and an unlicensed mobile access network
controller (UNC) 140. The UNC 140 communicates with
telecommunications network 104 using a base station controller
interface 126B that is similar to base station controller interface
126A, and includes a GSM A interface and Gb interface. Indoor base
station 128 and indoor network controller 132 may include software
entities stored in memory and executing on one or more
microprocessors (not shown in FIG. 1A) adapted to perform protocol
conversion.
[0037] Indoor base station 128 and UMA network controller 140 may
also include software entities stored in memory and executing on
one or more microprocessors (not shown in FIG. 1A) adapted to
perform protocol conversion.
[0038] The unlicensed wireless channel 136 is facilitated by a
radio link employing a wavelength (or wavelength range) in an
unlicensed, free spectrum (e.g., spectrum around 2.4 GHz, 5 GHz,
11-66 GHz). An unlicensed wireless service hosting unlicensed
wireless channel 136 may have an associated communication protocol.
As examples, the unlicensed wireless service may be a Bluetooth.TM.
compatible wireless service, or a wireless local area network (LAN)
(WiFi) service (e.g., the IEEE 802.11a, b, or g wireless standard).
This provides the user with potentially improved quality of service
in the service regions of the unlicensed wireless service (i.e.,
within the service range of a corresponding AP). Thus, when a
subscriber is within range of the unlicensed AP, the subscriber may
enjoy low cost, high speed, and high quality voice and data
services. In addition, the subscriber enjoys extended service range
since the handset can receive services deep within a building at
locations that otherwise may not be reliably serviced by a licensed
wireless system. At the same time, the subscriber can roam outside
the range of the unlicensed AP without dropping communications.
Instead, roaming outside the range of the unlicensed AP results in
a seamless handoff (also referred to as a handover) wherein
communication services are automatically provided by the licensed
wireless system, as described in more detail in U.S. patent
application Ser. No. 10/115,833, the contents of which are hereby
incorporated by reference.
[0039] Mobile station 102 may include a microprocessor and memory
(not shown) that stores computer program instructions for executing
wireless protocols for managing communication sessions. As
illustrated in FIG. 1B, in one embodiment the mobile station 102
includes a layer 1 protocol layer 142, layer 2 protocol layer 144,
and a layer 3 signaling protocol layer for the licensed wireless
service that includes a radio resource (RR) sublayer 146, a
mobility management (MM) sublayer 148, and a call management (CM)
layer 150. It will be understood that the level 1, level 2, and
level 3 layers may be implemented as software modules, which may
also be described as software "entities." In accordance with a
common nomenclature for licensed wireless services, layer 1 is the
physical layer, i.e., the physical baseband for a wireless
communication session. The physical layer is the lowest layer of
the radio interface and provides functions to transfer bit streams
over physical radio links. Layer 2 is the data link layer. The data
link layer provides signaling between the mobile station and the
base station controller. The RR sublayer is concerned with the
management of an RR-session, which is the time that a mobile
station is in a dedicated mode, as well as the configuration of
radio channel, power controller, discontinuous transmission and
reception, and handovers. The mobility management layer manages
issues that arise from the mobility of the subscriber. The mobility
management layer may, for example, deal with mobile station
location, security functions, and authentication. The call control
management layer provides controls for end-to-end call
establishment. These functions for a licensed wireless system are
well known by those in the art of wireless communication.
[0040] The mobile station may also include an unlicensed wireless
service physical layer 152 (i.e., a physical layer for unlicensed
wireless service such as Bluetooth, WiFi, or other unlicensed
wireless channel (e.g., WiMAX)). The mobile station also includes
an unlicensed wireless service level 2 link layer 154, and an
unlicensed wireless service radio resource sublayer(s) 156. An
access mode switch 160 is included for the mobile management 148
and call management layers 150 to access the unlicensed wireless
service radio resource sublayer 156 and unlicensed wireless service
link layer 154 when the mobile station 102 is within range of an
unlicensed AP 128 and to support switching between licensed RR
sublayer 146 and unlicensed wireless service RR sublayer 156.
[0041] The unlicensed radio resource sublayer 156 and unlicensed
link layer 154 may include protocols specific to the unlicensed
wireless service utilized in addition to protocols selected to
facilitate seamless handoff between licensed and unlicensed
wireless systems. Consequently, the unlicensed radio resource
sublayer 156 and unlicensed link layer 154 need to be converted
into a format compatible with a conventional base station
controller interface protocol 126 recognized by a MSC, SGSN, or
other voice or data network.
[0042] Referring to FIG. 1C, in one embodiment of the present
invention, the mobile station 102, AP 128 and UNC 140 provide an
interface conversion function to convert the level 1, level 2, and
level 3 layers of the unlicensed service into a conventional base
station subnetwork (BSS) interface 126B (e.g., an A-interface or a
Gb-interface). As a result of the protocol conversion, a
communication session may be established that is transparent to the
voice network/data network 104, i.e., the voice/data network 104
uses its standard interface and protocols for the communication
session as it would with a conventional communication session
handled by a conventional base transceiver station. For example, in
some embodiments the mobile station 102 and UNC 140 are configured
to initiate and forward location update and service requests. As a
result, protocols for a seamless handoff of services that is
transparent to voice/data network 104 are facilitated. This
permits, for example, a single phone number to be used for both the
licensed wireless service and the unlicensed wireless service.
Additionally, the present invention permits a variety of services
that were traditionally offered only through licensed wireless
services to be offered through an unlicensed wireless service. The
user thus gets the benefit of potentially higher quality service
when their mobile station is located within the area serviced by a
high bandwidth unlicensed wireless service while also having access
to conventional phone services.
[0043] The licensed wireless service may comprise any licensed
wireless service having a defined BSS interface protocol 126 for a
voice/data network 104. In one embodiment, the licensed wireless
service is a GSM/GPRS radio access network, although it will be
understood that embodiments of the present invention include other
licensed wireless services. For this embodiment, the UNC 140
interconnects to the GSM core network via the same base station
controller interfaces 126 used by a standard GSM BSS network
element. For example, in a GSM application, these interfaces are
the GSM A-interface for circuit switched voice services and the GSM
Gb interface for packet data services (GPRS). In a UMTS (Universal
Mobile Telecommunications System) application of the invention, the
UNC 140 interconnects to the UMTS network using a UMTS lu-cs
interface for circuit switched voice services and the UMTS lu-ps
interface for packet data services. In a CDMA application of the
invention, the UNC 140 interconnects with the CDMA network using
the CDMA A1 and A2 interfaces for circuit switched voice services
and the CDMA A10 and A11 interfaces for packet data services.
[0044] In a GSM/GPRS embodiment, UNC 140 appears to the GSM/GPRS
core network as a GSM BSS network element and is managed and
operated as such. In this architecture the principle elements of
transaction control (e.g., call processing) are provided by higher
network elements; namely the MSC 110 visitor location register
(VLR) and the SGSN 114. Authorized mobile stations are allowed
access to the GSM/GPRS core network either directly through the GSM
radio access network if they are outside of the service area of an
AP 128 or via the UMA network system if they are within the service
area of an AP.
[0045] Since a communication session hosted by the UMA architecture
100 is transparent to a voice network 112 or data network 116, the
unlicensed wireless service may support all user services that are
typically offered by a wireless service provider. In the GSM case,
this typically includes the following basic services: Telephony;
Emergency call (e.g., E911 calling in North America); Short
message, mobile-terminated point-to-point (MT/PP); Short message,
mobile-originated point-to-point (MO/PP); GPRS bearer services;
Handover (outdoor-to-indoor, indoor-to-outdoor, voice, data, SMS,
SS). Additionally, GSM may also support, various supplementary
services that are well-known in the art.
[0046] FIG. 2A provides an overview of a level 1, level 2, and
level 3 GSM-related protocol architecture for one embodiment of
mobile station 102 that provides unlicensed radio links via
Bluetooth signaling. As illustrated, there are two logical radio
resource (RR) management entities: the GSM RR entity 202 and the
UMA-RR entity 204. The protocol architecture includes a GSM
baseband level 1 layer 206, GSM level 2 link layer (LAPDm) 208,
Bluetooth baseband level 1 layer 210, Bluetooth level 2 layers 211
including a layer 2 connection access procedure (L2CAP) layer 212
and a BNEP layer 213, an access mode switch 214, and upper layer
protocols 216. When the mobile station is operating in an UMA mode,
the UMA-RR entity 204 is the current "serving" RR entity providing
service to the mobility management (MM) sublayer via the designated
service access point (RR-SAP). The GSM RR entity is detached from
the MM sublayer in this mode. The UMA-RR entity 204 provides a new
set of functions, and is responsible for several tasks. First the
UMA-RR entity is responsible for discovery of UMA coverage and UMA
registration. Second, the UMA-RR entity is responsible for
emulation of the GSM RR layer to provide the expected services to
the MM layer; i.e., create, maintain and tear down RR connections.
All existing GSM 04.07 primitives defined for the RR-SAP apply. The
plug-in of UMA-RR entity 204 is made transparent to the upper layer
protocols in this way. Third, a UMA-RR entity 204 module is
responsible for coordination with the GSM RR entity to manage
access mode switching and handover, as described in further detail
in application Ser. No. 10/688,470 referenced above.
[0047] FIG. 2B provides an overview of a level 1, level 2, and
level 3 GSM-related protocol architecture for one embodiment of
mobile station 102 that provides unlicensed radio links via IEEE
802.11 signaling. All of the entities and layers are the same as
described above for FIG. 2A, except that the Bluetooth layers have
been replaced with an 802.11 PHY layer 218 and an 802.11 MAC layer
220.
[0048] FIG. 3A illustrates the Up interface protocol architecture
in support of circuit switched (CS) Domain signaling, as well as
UMA-specific signaling, according to one embodiment. The MSC
sublayers are conventional, well known features known in the art in
regards to the message transfer part (MTP) interfaces MTP1 302,
MTP2 304, and MTP3 306, signaling connection control part (SCCP)
308, base station system application part (BSSAP) 310, mobility
management interface 312, and connection management interface
314.
[0049] The UMA-RR protocol supports the UMA "layer 3" signaling
functions via UMA-RR layers 204 provided by each of the mobile
station 102 and UNC 140. The UNC 140, acting like a BSC, terminates
UMA-RR protocol messages and is responsible for the interworking
between these messages and the analogous A-interface messages.
[0050] The layers below the UMA-RR layer 204 in each of mobile
station 104 and UNC 140 include a TCP layer 316, a remote IP layer
318, and an IPSec (IP security) layer 320. As an option, a standard
Secure Socket Layer (SSL) protocol running over TCP/IP (not shown)
may be deployed in place of IPSec layer 320.
[0051] Lower-level IP connectivity between mobile station 102 and
UNC 140 is supported by appropriate layers hosted by an intervening
access point 128 and broadband IP network 138 (i.e., the access
network 138 shown in FIG. 1A). The components for supporting the IP
transport layer (i.e., the conventional network layer 3 under the
seven-layer OSI model) include a transport IP layers 322 for each
of the mobile station 104, AP 128, and IP network 138, and an IP
layer 322A at UNC 140.
[0052] At the lowest layers (i.e., the physical and data link
layers), mobile station 104 and AP 128 are depicted as providing
unlicensed lower layers 324, while each of AP 128, IP network 138,
and UNC 140 provide appropriate access layers 326. Typically,
access layers 326 will include conventional Ethernet PHY and MAC
layers (IEEE 802.3), although this is not limiting.
[0053] As shown in FIGS. 3A and 3B, the unlicensed layers lower
layers 324 will depend on whether the unlicensed radio link uses
Bluetooth signaling or IEEE 802.11 signaling. The Bluetooth lower
layers depicted in FIG. 3A correspond to the mobile station
architecture of FIG. 2A, and include a Bluetooth baseband layer
210, an L2CAP layer 212, and a BNEP layer 213. Meanwhile, the
801.11 lower layers shown in FIG. 3B correspond to the mobile
station architecture of FIG. 2B, and include a 802.11 PHY layer 218
and in 802.11 MAC layer 220.
[0054] FIG. 3D illustrates the Up CS domain voice bearer protocol
architecture in support of GSM voice transmission, according to one
embodiment. In addition to the like named and referenced components
common to the architectures of FIGS. 3D and 3C, facilities are
provided for supporting GSM voice transmission. For the MSC 110,
these components include conventional components for supporting GSM
voice transmissions, and are depicted as physical layers 330 and
audio 332, with similar components being deployed in UNC 140. Each
of mobile station 102 and UNC 140 now include a GERAN (GSM Edge
Radio Access Network) codec 334 and an RTP/UDP layer 336.
[0055] Under the architecture of FIG. 3D, audio flows over the Up
interface according to the RTP framing format defined in RFC 3267
and RFC 3551. When operating in UMA mode, support for AMR FR as
specified in TS 26.103 is supported. Other codecs may also be
supported, such as G.711.
[0056] As noted above, the mobile station may be, for example, a
wireless phone, smart phone, personal digital assistant, or mobile
computer. The mobile station may also be, for example, a fixed
wireless device providing a set of terminal adapter functions for
connecting Integrated Services Digital Network (ISDN) or Plain Old
Telephone Service (POTS) terminals to the wireless system.
[0057] Other terminal adapter types than those listed above may be
employed with embodiments of the present invention. For example:
(1) a terminal adapter that supports cordless telephones rather
than POTS phones; (2) a terminal adapter that supports standard
Session Initiation Protocol (SIP) telephones; and (3) a terminal
adapter that also integrates a corded handset and user interface,
such as one would find on a desk phone. In each case, the invention
described herein describes how these terminal adapter functions can
be connected to the wireless system via the unlicensed network.
[0058] The use of other standard Bluetooth capabilities together
with embodiments of the present invention is possible. For example,
there is a Bluetooth standard capability called "SIM Access
Profile" that allows one Bluetooth device (e.g., an embedded cell
phone subsystem in a car) to access the SIM that is in another
Bluetooth device (e.g., the user's normal cell phone), allowing the
first device to take on the "personality" associated with the SIM
(i.e., that of the user's normal cell phone). The embodiments
described above could make use of this standard capability to give
the terminal adapter-attached devices (e.g., a POTS phone) the
personality of the user's cell phone.
Media Signaling
[0059] In the present description, the GSM BSSMAP (Base Station
Subsystem Management Application Part) protocol is modified for use
over the interface between an UNC (UMA (Unlicensed Mobile Access)
Network Controller) and an MSC (Mobile Switching Center) or a 3GPP
(Third Generation Partnership Project) Release 4 MSC Server. This
MSC server uses the "Release 4 distributed MSC Architecture" as
defined in the 3GPP TS 23.002 standard. Modifications are made to
the BSSMAP protocol and the A interface.
[0060] FIG. 4, shows a conventional context for an A Interface of a
UNC and MSC system architecture. As shown in FIG. 4, customer
premises equipment (CPE) 411 is coupled through a broadband access
network 413, such as a wide area network or the Internet to a UNC
415. In the example of FIG. 4, the CPE is shown as a mobile
station, such as a wireless or mobile phone shown as 102 in FIG. 1,
coupled through an Up radio interface to a wireless access point
(AP) shown as 128 in FIG. 1. A variety of types of CPE
implementations may be used instead of the MS, AP combination
shown. For example an IBS (Indoor Base Station), a VoIP (Voice over
Internet Protocol) telephony modem, a UMA (Universal Mobile Access)
modem or a private IP branch exchange may be used.
[0061] The UNC, which may be similar to the UNC shown as 140 in
FIG. 1, is shown as including a security gateway 417 to terminate
the secure tunnel between the MS and the UNC. The security gateway
is coupled to a control server and to a media gateway 420 or TRAU
(Transcoder and Rate Adaptation Unit). The control server handles
signaling with a PLMN 421. In one embodiment, the UNC emulates a
BSC (Base Station Controller) and uses signaling protocols, such as
A interface protocols designed for communication between an MSC and
a BSC. The UNC may also include other components depending on the
particular implementation. In one embodiment, the UNC is in the
form of an INC (Internet Protocol Network Controller)
[0062] FIG. 4 shows a few of the components of the PLMN 421 which,
in this example, includes a telephony switching center 425, such as
an MSC Call Server. The MSC Call Server has a DTAP (Direct Transfer
Application Part) and BSSMAP connection to the UNC. The PLMN also
has a media gateway 427 that is coupled to the media gateway 420 of
the UNC and to the MSC Call Server. The media gateway and the MSC
Call Server communicate with the UNC using the A interface. The MSC
Call Server and media gateway are further coupled to the rest of
the PLMN 429, which may include SGSNs, GGSNs, MSC servers, and
media gateways as well as BSSs and other UNCs, etc. The PLMN may
have further connections to the Internet, the PSTN (Public Switched
Telephone Network), and other resources.
[0063] FIG. 5, shows the impact of modifications to the A Interface
on the UNC and MSC system architecture. As shown in FIG. 5, the
modifications allow traffic to be communicated between a UMA
subscriber and a PLMN without a media gateway or TRAU (Transcoder
and Rate Adaptation Unit) function in the UNC. This reduces the
cost of the system and improves the system's quality.
[0064] As shown in FIG. 5, the mobile station and AP 511 are
coupled through a broadband access network 513 to a UNC 515. The
UNC includes a security gateway 517 and a control server 519, but
no media gateway. The PLMN 521 includes an MSC Call Server 525
coupled to the UNC control server and a media gateway 527 which in
this case is coupled to the security gateway 517 of the UNC 515.
The MSC Call Server and media gateway are coupled to the rest of
the PLMN 529, which may include many other resources.
[0065] In the enhanced UMA architecture of FIG. 5, the UNC and the
MSC communicate with a modified set of messages that may be based
on the standard BSSMAP messages used for communications between an
MSC and a BSC. The MSC Call Server and the media gateway
communicate using messages that may be based on the standard A
interface messages. BSSMAP messages that may be modified include
ASSIGNMENT REQUEST, ASSIGNMENT COMPLETE, HANDOVER REQUEST, and
HANDOVER DETECT.
Message Structures
[0066] Capabilities may be added to the system by adding some
additional messages in order to support UMA features. These
messages may include CHANNEL MODE MODIFY REQUEST, CHANNEL MODE
MODIFY ACKNOWLEDGE, and UPLINK QUALITY INDICATION. These messages
and the modified messages are described in more detail below. These
new messages may be supported within the existing BSSMAP message
system by assigning new message type IE (information element)
values to them. Examples of possible IE values are as follows:
TABLE-US-00001 TABLE 1 Channel Mode Modify 10000000 Channel Mode
Modify Acknowledge 10001001 Uplink Quality Indication 10001010
[0067] The ASSIGNMENT REQUEST message is sent from the MSC to the
UNC via the relevant SCCP (Signaling Connection Control Part)
connection in order to request the UNC to assign radio resources
and to establish a terrestrial connection, the attributes of the
connection in terms of signaling and of bearer traffic are defined
within the message. The message is composed of a set of IEs
(information elements) of various types. Some of this message's IEs
are listed below.
TABLE-US-00002 TABLE 2 CIC (Carrier This IE is an optional part of
the BSSMAP message Identification Code) and is not needed with the
modified BSSMAP message IP (Internet These IEs are used to describe
the VoIP connection Protocol) Address parameters that have been
allocated by the MSC. Sample Size RTP UDP Port RTCP UDP Port
Payload Type The Payload Type IE can be used in a modified message
if a payload with a dynamic type is used RTP Redundancy The RTP
Redundancy Information IE is included if Configuration the speech
codec FR AMR is signaled.
[0068] The ASSIGNMENT COMPLETE message is sent from the UNC to the
MSC in response to the ASSIGNMENT REQUEST message and indicates
that the requested assignment has been completed. Some of this
message's IEs are listed below.
TABLE-US-00003 TABLE 3 IP Address These IEs are used to describe
the VoIP connection Sample Size parameters that have been allocated
by the UNC RTP UDP Port Payload Type The Payload Type IE may be
used if a dynamic payload type is used. It defines the Payload Type
selected by the UMA MS RTP The RTP Redundancy Information IE may be
used if the Redundancy speech codec FR AMR is specified. It defines
RTP Configuration redundancy information adjusted based on the UMA
MS capabilities
[0069] The HANDOVER REQUEST message is sent from the MSC to the UNC
via the relevant SCCP connection to indicate that the UMA MS is to
be handed over to the UMAN (UMA Network). This corresponds to
situations in which a connection is handed over from another BSS
handing over to the same MSC or another MSC rather than when a call
is initiated and an assignment is requested. Some of this message's
IEs are listed below.
TABLE-US-00004 TABLE 4 Sample Size As with the ASSIGNMENT REQUEST,
these IP Address elements may be used to describe the VoIP RTP UDP
Port connection parameters that have been RTCP UDP Port allocated
by the MSC Payload Type As with the ASSIGNMENT REQUEST, the Payload
Type IE is included if a dynamic payload type is used Multi Rate As
with the ASSIGNMENT REQUEST, the Multi-rate Configuration
Configuration IE is included if the speech codec FR AMR is signaled
RTP Redundancy As with the ASSIGNMENT REQUEST, the RTP
Configuration Redundancy Information IE is included if the speech
codec FR AMR is signaled
[0070] The HANDOVER DETECT message is sent by the UNC to the MSC in
response to the HANDOVER REQUEST message and indicates that the UMA
MS has successfully accessed the UMA system. This message's IEs are
similar to that of the ASSIGNMENT COMPLETE message. Some of this
message's IEs are listed below.
TABLE-US-00005 TABLE 5 Sample Size As with the ASSIGNMENT COMPLETE
message, RTP UDP Port these IEs describe the VoIP connection
parameters IP Address that have been allocated by the UNC RTCP UDP
Port Payload Type As with the ASSIGNMENT COMPLETE message, the
Payload Type IE is used if a dynamic Payload Type is used. It
defines the Payload Type selected by the MS RTP Redundancy As with
the ASSIGNMENT COMPLETE message, the Configuration RTP Redundancy
Information IE is used if the speech codec FR AMR is signaled. It
defines RTP redundancy information adjusted based on the MS
capabilities
[0071] The CHANNEL MODE MODIFY message is sent by the MSC to the
UNC to request modifications related to an existing UMA bearer
channel and associated RTP stream. Such an existing bearer channel
and RTP stream would likely be established through the ASSIGNMENT
REQUEST message or the HANDOVER REQUEST message. The IEs are
similar to those described above and a list follows. In one
embodiment, the message is shortened by including only IEs that
describe requested modifications from the existing bearer channel
and associated RTP stream.
TABLE-US-00006 TABLE 6 Channel Mode These IEs are included if the
modification of the Sample Size associated parameter is requested;
i.e. Sample Size is IP Address included if Sample Size is modified
and is not included if RTP UDP Port it remains the same RTCP UDP
Port RTP Redundancy Configuration Multi Rate The Multi Rate
Configuration IE may be used only when Configuration the speech
codec signaled is FR AMR and when the RTP Redundancy configuration
is modified
[0072] The CHANNEL MODE MODIFY ACKNOWLEDGE message is sent by the
UNC to the MSC in response to the CHANNEL MODE MODIFY message to
acknowledge modifications related to the existing UMA RR bearer
channel and associated RTP stream. This message contains IEs
similar to the response messages mentioned above. Some are listed
below.
TABLE-US-00007 TABLE 7 Channel Mode These IEs are included if the
modification of the Sample Size associated parameter is requested;
i.e. Sample Size is RTP Redundancy included if Sample Size is
modified and is not Configuration included if it remains the same
Multi Rate The Multi Rate Configuration IE is included when the
Configuration speech codec signaled is FR AMR and when the RTP
Redundancy configuration is modified
[0073] A further message, an UPLINK QUALITY INDICATION message can
be sent by the MSC to the UNC as a notification that the uplink
quality deteriorated below the threshold and can not be further
improved with channel modification. This can be used instead of a
CHANNEL MODE MODIFY ACKNOWLEDGE message or as a separate message
sent on its own timing.
Modified Protocol Architectures
[0074] FIG. 6A illustrates a modification to the Up interface
protocol architecture of FIG. 3A in support of circuit switched
(CS) Domain signaling, as well as UMA-specific signaling, according
to one embodiment. The MSC sublayers are similar to those described
above for FIG. 3A. The BSSMAP protocol (part of BSSAP 610),
however, is modified to support the modified and additional
messages over the modified A interface between the UNC and the MSC.
This may include use of the modified and additional A-interface
messages described above. The layers below the Up interface
protocols are not changed.
[0075] FIG. 6B illustrates a modification of Up Audio protocol
architecture, according to an embodiment, that may be implemented
in the architecture of FIG. 5. This Up Audio architecture allows
audio bearer packets 372 to be carried straight through from the MS
102 to the R4 Media Gateway 527 of the PLMN 521. The same applies
to remote IP packets 318 and above. In FIG. 6B, this includes
RTP/UDP signaling 356.
[0076] As illustrated in FIG. 6B, the UNC 140 and media gateway 527
employ conventional facilities for supporting Up audio bearer data
packets, including lower layers 370 that may include access layers
326, transport IP 322 and an IPSec ESP layer 320. However, the
Remote IP layer 318, RTP/UDP layer 356 and Up audio layer 372 are
not shared with the access point 128, IP network 138 or UNC 140.
These are transmitted through these elements directly between the
MS and the media gateway.
[0077] Under the architecture of FIG. 6B, Up audio does not need to
be transcoded or repacketized for any of the intermediate elements
in the communication chain. The transcoding, signaling and codecs
of FIG. 3D are avoided. This eliminates the need for a media
gateway in the UNC, reducing costs and increasing reliability.
Example Signaling Transactions
[0078] FIG. 7 shows one procedure associated with successfully
establishing a voice channel between the MS 511 and the MSC (i.e.,
shown as consisting of a MSC Call Server 525 and a Media Gateway
527) for mobile-originated or mobile-terminated call purposes. FIG.
7 does not show any connection signaling associated with the call
that is not directly related to the connection to the MS (e.g.,
ISUP (ISDN (Integrated Services Digital Network) User Part)
signaling towards the other party.
[0079] Initially, a mobile-originated or mobile-terminated call
establishment is in progress. The MSC Call Server determines that a
speech channel to the target MS is required. Accordingly, at line
A, the MSC Call Server requests that the media gateway (MG) 527
create a VoIP connection. The communication between the MSC Call
Server and the MG may be in the form of a media gateway control
protocol, such as H.248. Using this protocol, many different
parameters for the VoIP connection may be set. This request
includes an identification of the codec or codecs that are allowed
for the connection. At line B, the MG creates the connection and
returns a connection ID and a local connection description that
includes the assigned MG IP address and port number for the
connection.
[0080] At line C, the MSC Call Server sends an ASSIGNMENT-REQUEST
message to the UNC. The ASSIGNMENT-REQUEST message may include any
of the IEs mentioned above and may include information describing
the connection to the MG encoded into a BSSMAP format.
[0081] Upon receiving the ASSIGNMENT-REQUEST message, the UNC at
line D sends a URR-ACTIVATE-CHANNEL message to the MS at line D.
This message includes the information received in the
ASSIGNMENT-REQUEST message from the MSC Call Server. The
URR-ACTIVATE CHANNEL message together with the other messages
between the MS and the UNC, may be based on those defined in the
UMA (Universal Mobile Access) standard, however other messages may
be used to signal the CPE to activate a channel.
[0082] At line E, the MS establishes a VoIP connection to the IP
address and port identified in the URR-ACTIVATE-CHANNEL message.
The MS then returns a URR-ACTIVATE-CHANNEL-ACK message to the UNC,
including the required connection information. This information may
include such parameters as: RTP UDP Port number, sample size,
payload type and RTCP UDP Port number. At line F, the UNC sends the
URR-ACTIVATE-CHANNEL-COMPLETE message to the MS.
[0083] If the connection is not established, then the UNC may send
a BSSMAP ASSIGNMENT-FAILURE message (not shown) to the MSC Call
Server. The MSC Call Server then initiates call clearing using, for
example, a BSSMAP CLEAR-COMMAND message.
[0084] Using the information received from the MS in the
URR-ACTIVATE CHANNEL ACK message, the UNC can provide full
connection information back to the MSC Call Server. At line G, the
UNC signals the MSC Call Server that assignment is complete using
an ASSIGNMENT-COMPLETE message, including the connection
information received from the MS.
[0085] At line I, the MSC Call Server requests the MG to modify the
previously-created VoIP connection to use the codec and remote IP
address and port identified in the ASSIGNMENT-COMPLETE message. At
line J the MG modifies the connection, and at line K, RTP packets
are flowing in both directions between the MS and the MG, via the
broadband IP network. Call establishment may then continue to any
other terminals involved in the call.
[0086] FIG. 8 shows an example of messages that may be used to
establish a voice channel between an MS 511 and the MSC 525, 527
for GSM-to-AP handover purposes. As in FIG. 7, the signaling not
directly related to the MS to MSC Call Server connection is not
shown (e.g., GSM signaling towards the other called party).
[0087] In FIG. 8, a GSM-to-UMA or AP handover is in progress. In
other words, the MS 511 is in a call through a GSM air interface to
a BTS (Base Transceiver Station). The MS is in the process of
handing over that call to the UMAN. To accomplish the handover, a
speech channel between the MS and the MSC may be used. Accordingly,
at line A, the MSC Call Server 525 requests that the media gateway
(MG) 527 create a VoIP connection. This request includes the
parameters for the codec or codecs that are allowed for the
connection. At line B, the MG creates the connection and returns a
connection ID and a local connection description that includes the
assigned MG IP address and port number for the connection.
[0088] Using the received information, the MSC Server encodes any
required connection description information in a HANDOVER-REQUEST
message as described above. At line C, this message is forwarded to
the UNC, and at line D, the UNC responds with a standard BSSMAP
HANDOVER-REQUEST-ACK message containing an encapsulated
HANDOVER-COMMAND message formulated according to the standard GERAN
(GSM EDGE (Enhanced Data Rate for GSM Evolution) Radio Access
Network) procedure.
[0089] At line E, the MSC Server directs a GSM BSC (Base Station
Controller) (not shown) to send a HANDOVER-COMMAND message to the
MS via the GSM air interface (not shown). At line F, in response to
the HANDOVER-COMMAND message, the MS sends an URR-HANDOVER-ACCESS
message to the UNC containing the HANDOVER-COMMAND that it received
through the GSM air interface. The UNC correlates this signal with
the handover request that it responded to on line C.
[0090] Lines G-I show operations similar to those of lines D-F of
FIG. 7. At line G the UNC sends an URR-ACTIVATE-CHANNEL message to
the MS that includes the information received in the
HANDOVER-REQUEST message from the MSC Call Server. At line H, the
MS, returns a URR-ACTIVATE-CHANNEL-ACK message to the UNC including
the required connection information such as: RTP UDP Port #, sample
size, payload type and RTCP UDP Port #. At line I, the UNC sends
the URR-ACTIVATE-CHANNEL-COMPLETE message to the MS, completing the
connection between the MS and the UNC.
[0091] At line J, the UNC signals the MSC Call Server that the MS
has accessed the UNC system via the HANDOVER-DETECT message
described above, that includes the connection information received
from the MS. Lines K-M show signaling similar to that of lines H-J
in of FIG. 7. Line K shows RTP packets flowing in one direction
from the MS to the MG, via the UNC 515. At line L, the MSC Call
Server requests the MG to modify any previously created VoIP
connection to use the codec and remote IP address and port
identified in the HANDOVER-DETECT message. At line M, the MG
modifies the connection, and at line N, RTP packets are flowing in
both directions between the MS and the MG, via the access
router.
[0092] At line 0, the MS signals the successful completion of the
handover by sending the URR-HANDOVER-COMPLETE message to the UNC.
At line P, the UNC signals successful completion of the handover by
sending a BSSMAP HANDOVER-COMPLETE message to the MSC Call Server,
and at line Q, the MSC Server responds by switching the call path
from GSM public air interface to the UNC. This allows the call to
continue uninterrupted at line R.
[0093] The handover may fail for any number of reasons which may
result in the mobile retaining the connection with the GSM BTS, or
it may result in the call being dropped. For example, if the MSC
Server fails to create the MG connection, or if the UNC connection
is not established, then the MSC Server may abort the handover. If
the MSC Server fails to modify the MG connection, then the MSC
Server may clear the call (e.g., send a BSSMAP CLEAR-COMMAND
message).
[0094] FIG. 9 shows an example of modifying the bearer connection
between the MS and the MSC. In the example of FIG. 9, a mobile
originated or mobile terminated call is in progress and the MSC
Call Server determines that the bearer connection has to be
modified. This may be due, for example, to detecting the loss of
too many RTP packets. One example of a modification of a bearer
connection is to apply RTP Redundancy. At line A, the RTP session
is established and RTP packets are exchanged in both directions.
The MSC determines that a modification to the bearer connection is
called for and determines what parameters need to be modified.
Accordingly, at line B, the MSC prepares a CHANNEL-MODE-MODIFY
message, as described above, specifying the parameters that need to
be modified and sends this message to the UNC.
[0095] At line C, the UNC constructs a URR-CHANNEL-MODE-MODIFY
message based on the request form the MSC and forwards it to the
MS. At line D, the MS modifies the connection in accordance with
the request and responds with an acknowledgment message,
URR-CHANNEL-MODE-MODIFY ACKNOWLEDGMENT. The UNC forwards the
acknowledgment to the MSC at line E. However, if the MS is not able
to handle the requested modification, then the MS will so indicate
in the acknowledgment message.
[0096] In the example of modifying the channel mode to include RTP
redundancy, the MS can reply by sending an acknowledgment that does
not include the requested modification to the IE corresponding to
RTP redundancy. In another example, if the modification relates to
IP addresses and UDP ports, then if the MS is not able to make the
change, the call may continue on the original ports, or if these
are unavailable then the call may be cleared. In parallel, the MS
and MSC modify the RTP stream associated with this connection and,
at line F, the modified RTP packets are now exchanged between the
MS and MSC. The call continues at line G using the modified RTP
stream.
[0097] FIG. 10 shows an example of providing an indication of the
quality of the uplink channel from the MSC to the MS. These
operations may be used by the MSC to notify the UNC when the uplink
quality associated with a particular bearer connection falls below
a predefined threshold or experiences a large change. It may also
be used if the uplink quality degrades and is not improved by a
channel mode modify procedure as shown in FIG. 9.
[0098] Initially, a mobile originated or mobile terminated call is
in progress. At line A, an RTP session is established and RTP
packets are exchanged in both directions. The MSC determines that
an uplink quality indication is to be sent. This may occur, for
example, because the uplink quality associated with the bearer
connection is below a predefined threshold for uplink quality and
all attempts to improve the quality have failed.
[0099] At line B, the MSC sends an UPLINK-QUALITY-INDICATION
message, such as the one described above, to notify the UNC. At
line C, the UNC constructs a URR-UPLINK-QUALITY-INDICATION message
based on the indication from the MSC and forwards it to the UMA MS.
Upon receiving such a message, the MS may take any appropriate
measure. In the example of FIG. 10, at line D, the MS initiates a
handover to a GERAN connection.
[0100] The particular equipment, services, sequences of events and
types of signals are provided above as examples only. While the
example of FIGS. 7, 8, 9, and 10 are presented in the context of a
VoIP WLAN AP and a GSM cellular network, appropriate modifications
may be made to comply with other types of networks and protocols.
In addition to a wireless mobile station and a wireless access
point, embodiments of the invention may be applied to other types
of subscriber equipment including enterprise systems and networks,
private and public switched networks and other wired, wireless and
hybrid systems that may connect to a UNC or similar device through
the Internet or through any other communications medium. In
addition to a UNC, embodiments of the invention may be applied to
other network devices that interface to a PLMN or PSTN. In addition
to a GSM architecture, embodiments of the invention may be applied
to other types of telecommunications networks, both wired and
wireless, these may include those based on CDMA, TDMA, PCS
(Personal Communication Services), PHS (Personal Handyphone System)
and other standardized protocols. The protocol architecture
diagrams described above are provided as examples only. Many of the
layers may be grouped, divided or identified differently to suit a
particular application. The components involved in communicating at
any particular layer may also be modified to suit a particular
application.
[0101] It is to be appreciated that a lesser or more equipped UNC,
AP, mobile station, private network, and public network than the
examples described above may be desirable for certain
implementations. Additional or different components, interfaces,
buses and capabilities may be used and additional devices may be
added to any of these components. Some of the illustrated
components may also be removed from the devices: The configuration
of the UNC, AP, mobile station, private network, and public network
may vary with different implementations depending upon numerous
factors, such as price constraints, performance requirements,
technological improvements, or other circumstances. It is not
necessary that the licensed frequencies be used for a portion of
the system nor that unlicensed frequencies be used for a portion of
the system. It is further not necessary that a portion of the
system be private and another portion be public.
[0102] Although the description of the various embodiments refers
primarily to using location information in establishing a VoIP
private network call through a GSM cellular telecommunications
system, the various embodiments may also be used with other types
of private communications systems and with other types of public
telecommunications networks. The various embodiments may be applied
to voice networks, data networks and combined networks whether they
are circuit switched or packet switched.
[0103] It will be understood that an embodiment of the present
invention relates to a computer storage product with a
computer-readable medium having computer code thereon for
performing various computer-implemented operations. The media and
computer code may be those specially designed and constructed for
the purposes of the present invention, or they may be of the kind
well known and available to those having skill in the computer
software arts. Examples of computer-readable media include, but are
not limited to: magnetic media such as hard disks, floppy disks,
and magnetic tape; optical media such as CD-ROMs and holographic
devices; magneto-optical media such as optical disks; and hardware
devices that are specially configured to store and execute program
code, such as application-specific integrated circuits ("ASICs"),
programmable logic devices ("PLDs") and ROM and RAM devices.
Examples of computer code include machine code, such as produced by
a compiler, and files containing higher-level code that are
executed by a computer using an interpreter. For example, an
embodiment of the invention may be implemented using Java, C++, or
other object-oriented programming language and development tools.
Another embodiment of the invention may be implemented in hardwired
circuitry in place of, or in combination with, machine-executable
software instructions.
[0104] The foregoing description, for purposes of explanation, use
specific nomenclature to provide a thorough understanding of the
invention. However, it will be apparent to one skilled in the art
that specific details are not required in order to practice the
invention. Thus, the foregoing descriptions of specific embodiments
of the invention are presented for purposes of illustration and
description. They are not intended to be exhaustive or to limit the
invention to the precise forms disclosed; obviously, many
modifications and variations are possible in view of the above
teachings. The embodiments were chosen and described in order to
best explain the principles of the invention and its practical
applications, they thereby enable others skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated. It
is intended that the following claims and their equivalents define
the scope of the invention.
TABLE-US-00008 APPENDIX I Table Of Acronyms AP Access Point ARFCN
Absolute RF Channel Number ATM Asynchronous Transfer Mode ATM VC
ATM Virtual Circuit BCCH Broadcast Common Control Channel BSC Base
Station Controller BSS Base Station Subsystem BSSGP Base Station
System GPRS Protocol BSSMAP Base Station System Management
Application Part BTS Base Transceiver Station CDMA Code Division
Multiple Access CGI Cell Global Identification CIC Circuit Identity
Code CM Connection Management CPE Customer Premises Equipment CS
Circuit Switched DTAP Direct Transfer Application Part FR AMR Full
Rate Adaptive Multi-Rate GERAN GSM Edge Radio Access Network GGSN
Gateway GPRS Support Node GMSC Gateway MSC GSM Global System for
Mobile Communication GPRS General Packet Radio Service GSN GPRS
Support Node GTP GPRS Tunnelling Protocol HLR Home Location
Register IAN Indoor Access Network (see also UMA Cell) IBS Indoor
Base Station IETF Internet Engineering Task Force INC Internet
Protocol Network Controller IP Internet Protocol ISDN Integrated
Services Digital Network ISP Internet Service Provider ISUP ISDN
User Part MAC Medium Access Control MAP Mobile Application Part MG
Media Gateway MM Mobility Management MS Mobile Station MSC Mobile
Switching Center MTP1 Message Transfer Part Layer 1 MTP2 Message
Transfer Part Layer 2 MTP3 Message Transfer Part Layer 3 PCM Pulse
Code Modulation PCS Personal Communications Services PLMN Public
Land Mobile Network POTS Plain Old Telephone Service PPP
Point-to-Point Protocol PPPoE PPP over Ethernet protocol PSTN
Public Switched Telephone Network QoS Quality of Service RF Radio
Frequency RFC Request for Comment (IETF Standard) RLC Radio Link
Control RR Radio Resource Management RTCP Real Time Control
Protocol RTP Real Time Protocol SAP Service Access Point SCCP
Signaling Connection Control Part SCO Synchronous
Connection-Oriented SDCCH Standalone Dedicated Control Channel SGSN
Serving GPRS Support Node SMC Short Message Service Centre SMS
Short Message Service SS Supplementary Service SSL Secure Sockets
Layer TCAP Transaction Capabilities Application Part TCP
Transmission Control Protocol TRAU Transcoder and Rate Adaptation
Unit UDP User Datagram Protocol UMA Unlicensed Mobile Access UMAN
Unlicensed Mobile Access Network UMTS Universal Mobile
Telecommunication System UNC UMA Network Controller (see also INC)
VLR Visited Location Register WLAN Wireless Local Area Network
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