U.S. patent application number 11/735208 was filed with the patent office on 2007-10-25 for wireless communication components and methods for multiple system communications.
This patent application is currently assigned to INTERDIGITAL TECHNOLOGY CORPORATION. Invention is credited to Amarnath Chitti, Debashish Purkayastha.
Application Number | 20070249390 11/735208 |
Document ID | / |
Family ID | 33493527 |
Filed Date | 2007-10-25 |
United States Patent
Application |
20070249390 |
Kind Code |
A1 |
Purkayastha; Debashish ; et
al. |
October 25, 2007 |
WIRELESS COMMUNICATION COMPONENTS AND METHODS FOR MULTIPLE SYSTEM
COMMUNICATIONS
Abstract
A method and a wireless transmit/receive unit (WTRU) for
communication in a first and a different second type of wireless
networks. The WTRU includes respective components configured for
wireless communication of user data with the respective first and
second type of wireless networks and an upper layer application
processing component configured to process user data. An interface
coupling the upper layer application processing component and the
respective types of wireless components selectively controls the
flow of user data. The interface include a controllable data buffer
switch that defines a multi-pronged bufferable path for user data
between the upper layer application processing component and
respective types of wireless components. A control device controls
the data buffer switch to buffer user data in connection with
switching user data flow from one prong of the multi-pronged
bufferable path to another prong of the multi-pronged bufferable
path. Implementation in an application specific integrated circuit
(ASIC) is provided.
Inventors: |
Purkayastha; Debashish;
(Pottstown, PA) ; Chitti; Amarnath; (East
Norriton, PA) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.;DEPT. ICC
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
INTERDIGITAL TECHNOLOGY
CORPORATION
3411 Silverside Road, Concord Plaza, Suite 105 Hagley
Building
Wilmington
DE
19810
|
Family ID: |
33493527 |
Appl. No.: |
11/735208 |
Filed: |
April 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11303376 |
Dec 16, 2005 |
7204746 |
|
|
11735208 |
Apr 13, 2007 |
|
|
|
10737369 |
Dec 16, 2003 |
6987985 |
|
|
11303376 |
Dec 16, 2005 |
|
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|
60476322 |
Jun 6, 2003 |
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Current U.S.
Class: |
455/552.1 |
Current CPC
Class: |
H04W 36/0066 20130101;
H04W 36/02 20130101; H04W 88/06 20130101; H04M 1/725 20130101; H04W
36/0033 20130101; H04M 2250/06 20130101 |
Class at
Publication: |
455/552.1 |
International
Class: |
H04M 1/00 20060101
H04M001/00 |
Claims
1. A wireless transmit/receive unit (WTRU) for communication in a
first and a different second two type of wireless networks
comprising: a first physical layer component and an associated
first physical layer control component configured for wireless
communication of user data with the first type of wireless network;
a second physical layer component and an associated second physical
layer control component configured for wireless communication of
user data with the second type of wireless network; an upper layer
application processing component configured to process user data;
an interface configured to couple the upper layer application
processing component and said first and second physical layer
control components including: a controllable data buffer switch
configured to define a multi-pronged bufferable path for user data
between the upper layer application processing component and said
first and second physical layer control components such that a
first prong of the multi-pronged bufferable path is configured to
communicate user data between the upper layer application
processing component and said first physical layer control
component and a second prong of the multi-pronged bufferable path
is configured to communicate user data between the upper layer
application processing component and said second physical layer
control component; and a data buffer switch control device
configured to control said data buffer switch to buffer user data
in connection with switching user data flow from one prong of the
multi-pronged bufferable path to another prong of the multi-pronged
bufferable path.
2. The WTRU of claim 1 wherein said first physical layer component
and associated first physical layer control component are
configured for UMTS wireless communications and said second
physical layer component and associated second physical layer
control component are configured for 802.11 WLAN
communications.
3. The WTRU of claim 2 wherein the multi-pronged bufferable path
for user data is configured to transport packet switched data.
4. The WTRU of claim 2 wherein a data path is defined for circuit
switch data between the upper layer application processing
component and the UMTS physical layer control component.
5. The WTRU of claim 2 wherein the interface includes a link
monitor and is configured to trigger the initiation of a wireless
link through a different type of wireless communication based upon
monitored link data meeting predetermined criteria.
6. The WTRU of claim 5 wherein the interface includes a Subscriber
Identity Module (SIM) reader configured to read a SIM containing a
user's identity.
7. The WTRU of claim 1 wherein the multi-pronged bufferable path is
configured to transport packet switched data.
8. The WTRU of claim 1 wherein the interface includes a link
monitor and is configured to trigger the initiation of a wireless
link through a different type of wireless communication based upon
monitored link data meeting predetermined criteria.
9. A method for a wireless transmit/receive unit (WTRU) for
communication in a first and a different second type of wireless
networks wherein the WTRU includes a first physical layer component
and an associated first physical layer control component configured
for wireless communication of user data with the first type of
wireless network, a second physical layer component and an
associated second physical layer control component configured for
wireless communication of user data with the second type of
wireless network and an upper layer application processing
component configured to process user data, the method comprising:
selectively controlling the flow of user data in an interface
coupling the upper layer application processing component and said
first and second physical layer control components including:
providing a controllable data buffer switch that defines a
multi-pronged bufferable path for user data between the upper layer
application processing component and said first and second physical
layer control components such that a first prong of the
multi-pronged bufferable path communicates user data between the
upper layer application processing component and said first
physical layer control component and a second prong of the
multi-pronged bufferable path communicates user data between the
upper layer application processing component and said second
physical layer control component; and controlling said data buffer
switch to buffer user data in connection with switching user data
flow from one prong of the multi-pronged bufferable path to another
prong of the multi-pronged bufferable path.
10. The method of claim 9 where the first physical layer component
and associated first physical layer control component are
configured for UMTS wireless communications and the second physical
layer component and associated second physical layer control
component are configured for 802.11 WLAN communications wherein
said controlling said data buffer switch to buffer user data is
performed in connection with switching between UMTS wireless
communications and 802.11 WLAN communications.
11. The method of claim 10 wherein the selectively controlling the
flow of user data is of transport packet switched data.
12. The method of claim 10 including defining a data path for
circuit switch data between the upper layer application processing
component and the UMTS physical layer control component.
13. The method of claim 10 including monitoring wireless
communications link data to trigger the initiation of a wireless
link through a different type of wireless communication based upon
monitored link data meeting predetermined criteria.
14. The method of claim 10 wherein the selectively controlling the
flow of user data includes reading a user's identity from a
Subscriber Identity Module (SIM).
15. The method of claim 9 wherein the selectively controlling the
flow of user data is of transport packet switched data.
16. The method of claim 9 including monitoring wireless
communications link data to trigger the initiation of a wireless
link through a different type of wireless communication based upon
monitored link data meeting predetermined criteria.
17. The method of claim 9 wherein the selectively controlling the
flow of user data includes reading a user's identity from a
Subscriber Identity Module (SIM).
18. An application specific integrated circuit (ASIC) configured to
provide a continuous communication session when a wireless
transmit/receive unit (WTRU) switches a wireless connection from a
first wireless communication interface to a second wireless
communication interface, the ASIC comprising: an application broker
configured to monitor control signaling between a lower layer
protocol engine and an upper layer application processing
component; and a communications broker configured to process all
user communication data flows and direct the data to the
appropriate wireless communication interface in the lower layer
protocol engine.
19. The ASIC according to claim 18 wherein the application broker
and communications broker provide a two-tier middleware
architecture that provides a continuous communication session and
enables integration of different wireless systems.
20. The ASIC according to claim 18 wherein the application broker
is configured to receive link status information from the lower
layer protocol engine and to determine whether to switch the
wireless connection from the first wireless communication interface
to the second wireless communication interface based on the quality
of service (QoS) of the wireless connection.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/303,376, filed Dec. 16, 2005, which is a
continuation of U.S. patent application Ser. No. 10/737,369, filed
Dec. 16, 2003, which claims the benefit of U.S. Provisional
Application No. 60/476,322 filed Jun. 6, 2003 which are
incorporated by reference as if fully set forth herein.
FIELD OF INVENTION
[0002] This application relates to components and methods for
wireless communication in multiple systems, and, in particular, to
mobile wireless transmit/receive units (WTRUs) capable of
continuous communications while switching from a wireless
connection with a first type of wireless system to a wireless
connection with a second type of wireless system, such as from a
Universal Mobile Telecommunications System (UMTS) to a wireless
local area network (WLAN) or vice versa.
BACKGROUND OF THE INVENTION
[0003] Wireless communication systems are well known in the art.
Generally, such systems comprise communication stations which
transmit and receive wireless communication signals between each
other. For network systems such as mobile cellular systems, there
are typically two types of communication stations, namely, base
stations which provide access to the network infrastructure and
wireless transmit/receive units (WTRUs) which conduct wireless
communications with the base stations.
[0004] There is a growing dependence upon wireless communications
in the home, office, and when traveling. It is not uncommon for a
user to have several different WTRUs such as different home,
office, and mobile wireless telephones. Accordingly, there is a
need to replace the use of multiple WTRUs with a single WTRU which
can be used in the home, office and when traveling.
[0005] In many commercial networks, a network of base stations is
provided wherein each base station is capable of conducting
multiple concurrent wireless communications with appropriately
configured WTRUs. In order to provide global connectivity for
wireless systems, standards have been developed and are being
implemented. One current standard in widespread use is known as
Global System for Mobile Telecommunications (GSM). This is
considered as a so-called Second Generation mobile radio system
standard (2G) and was followed by its revision (2.5G). GPRS and
EDGE are examples of 2.5G technologies that offer relatively high
speed data service on top of (2G) GSM networks. Each one of these
standards sought to improve upon the prior standard with additional
features and enhancements. In January 1998, the European
Telecommunications Standard Institute--Special Mobile Group (ETSI
SMG) agreed on a radio access scheme for Third Generation Radio
Systems called Universal Mobile Telecommunications Systems (UMTS).
To further implement the UMTS standard, the Third Generation
Partnership Project (3GPP) was formed in December 1998. 3GPP
continues to work on a common third generational mobile radio
standard.
[0006] A typical UMTS system architecture in accordance with
current 3GPP specifications is depicted in FIG. 1a. The UMTS
network architecture includes a Core Network (CN) interconnected
with a UMTS Terrestrial Radio Access Network (UTRAN) via an
interface known as Iu which is defined in detail in the current
publicly available 3GPP specification documents.
[0007] The UTRAN is configured to provide wireless
telecommunication services to users through WTRUs, called User
Equipments (UEs) in 3GPP, via a radio interface known as Uu. The
UTRAN has base stations, known as Node Bs in 3GPP, which
collectively provide for the geographic coverage for wireless
communications with UEs. In the UTRAN, groups of one or more Node
Bs are connected to a Radio Network Controller (RNC) via an
interface known as Iub in 3GPP. The UTRAN may have several groups
of Node Bs connected to different RNCs, two are shown in the
example depicted in FIG. 1a. Where more than one RNC is provided in
a UTRAN, inter-RNC communication is performed via an Iur
interface.
[0008] A UE will generally have a Home UMTS Network (HN) with which
it is registered and through which billing and other functions are
processed. By standardizing the Uu interface, UEs are able to
communicate via different UMTS networks that, for example, serve
different geographic areas. In such case the other network is
generally referred to as a Foreign Network (FN).
[0009] Under current 3GPP specifications, the Core Network of a
UE's HN serves to coordinate and process the functions of
Authentication, Authorization and Accounting (AAA functions). When
a UE travels beyond its Home UMTS Network, the HN's Core Network
facilitates the UE's use of a Foreign Network by being able to
coordinate the AAA functions so that the FN will permit the UE to
conduct communications. To assist in implementing this activity,
the Core Network includes a Home Location Register (HLR) which
tracks the UEs for which it is the HN and a Visitor Location
Register (VLR). A Home Service Server (HSS) is provided in
conjunction with the HLR to process the AAA functions.
[0010] Under current 3GPP specifications, the Core Network is
configured with connectivity to external systems such as Public
Land Mobile Networks (PLMN), Public Switch Telephone Networks
(PSTN), Integrated Services Digital Network (ISDN) and other Real
Time (RT) services via an RT service interface. A Core Network also
supports Non-Real Time services with the Internet. External
connectivity of the Core Network to other systems enables users
using UEs to communicate via their Home UMTS Network beyond the
area served by the HN's UTRAN. Visiting UEs can likewise
communicate via a visited UMTS Network, beyond the area served by
the visited UMTS's UTRAN.
[0011] Under current 3GPP specifications, the Core Network provides
RT service external connectivity via a Gateway Mobile Switching
Center (GMSC). The Core Network provides NRT service, known as
General Packet Radio Service (GPRS), external connectivity via a
Gateway GPRS Support Node (GGSN). In this context, a particular NRT
service may actually appear to a user to be a real time
communication due to the communication speed and associated
buffering of the TDD data packets forming the communication. One
example of this is voice communication via the Internet which can
appear to the user as a normal telephone call conducted by a
switching network, but is actually being conducted using an
Internet Protocol (IP) connection which provides Packet data
Service.
[0012] A standard interface known as GI is generally used between a
CN's GGSN and the Internet. The GI interface can be used with
Mobile Internet Protocols, such as Mobile IP v4 or Mobile IP v6 as
specified by the Internet Engineering Task Force (IETF).
[0013] Under current 3GPP specifications, to provide support for
both RT and NRT services from external sources for radio linked UEs
in a 3GPP system, the UTRAN must properly interface with the CN
which is the function of the Iu interface. To do this, the Core
Network includes a Mobile Switching Centre (MSC) that is coupled to
the GMSC and a Serving GPRS Support Node (SGSN) that is coupled to
the GGSN. Both are coupled with the HRL and the MSC is usually
combined with the Visitor Location Register (VLR).
[0014] The Iu interface is divided between an interface for Circuit
Switched communications (Iu-CS) and an interface for packet data
via Packet Switched communications (Iu-PS). The MSC is connected to
the RNCs of the UTRAN via the Iu-CS interface. The Serving GPRS
Support Node (SGSN) is coupled to the UTRAN's RNCs via the Iu-PS
interface for Packet Data Services.
[0015] The HLR/HSS is typically interfaced with the CS side of the
Core Network, MSC and GMSC via an interface known as Gr which
supports AAA functions through a Mobile Application Part (MAP)
Protocol. The SGSN and the GGSN of the CN are connected using
interfaces known as Gn and Gp.
[0016] Another type of wireless system, called a wireless local
area network (WLAN), can be configured to conduct wireless
communications with WTRUs equipped with WIAN modems. Currently,
WLAN modems are being integrated into many traditional
communicating and computing devices by manufactures. For example,
cellular phones, personal digital assistants, and laptop computers
are being built with one or more WLAN modems. Accordingly, there is
an increasing need to facilitate communications among such WTRUs
with WLAN modems as well as with different types of networks.
[0017] A popular wireless local area network environment with one
or more WLAN Access Points (APs), i.e., base stations, is built
according to the IEEE 802.11b standard. The wireless service areas
for such WLANs may be restricted to specified well defined
geographic areas known as "hot spots". Such wireless communication
systems are advantageously deployed in areas such as airports,
coffee shops, and hotels. Access to these networks usually requires
user authentication procedures. Protocols for such systems are not
yet fully standardized in the WLAN technology area, since the IEEE
802 family of standards is evolving. However, as noted above, the
CN of UMTS networks are designed for facilitating communication
with other networks such as WLANs.
[0018] In lieu of using a different WTRU in each different
environment, WTRUs can be provided with both UMTS and WLAN
capabilities, such as pocket PCs with separate UMTS and WLAN PCMCIA
card adapters. Separate card components enable a user to use
different types of networks via a single device, but does not
provide a WTRU capable of switching from one type of network to
another without a loss of connectivity. For example, a mobile WTRU
communicating with or seeking to communicate with a target WTRU may
travel into areas of poor signal quality where the communications
with a particular type of network that serves the target WTRU
becomes sporadic or nonexistent. In such cases, it would also be
desirable if the WTRU can not only roam for within the same type of
network, but also switch to a different type of network which
maintaining a communication session on an ongoing basis.
SUMMARY
[0019] A mobile wireless transmit/receive unit (WTRU), components
and methods therefor provide continuous communications capability
while switching from a wireless connection with a first type of
wireless system to a wireless connection with a second type of
wireless system.
[0020] Preferably, the WTRU is configured to switch wireless links
from a Universal Mobile Telecommunications System (UMTS) to a
wireless local area network (WLAN) or vice versa during a
continuous communication session. The invention is preferably
implemented by providing a n Application Broker for control
signaling and a Communications broker for user data flow which may
be embodied in an application specific integrated circuit
(ASIC).
[0021] A preferred WTRU in accordance with the invention includes a
protocol engine having at least two wireless communication
interfaces, each configured for wireless linking with a different
type of wireless network. Each communication interface is
preferably configured to pass control signals and user
communication data to a common application processing component. An
application broker is provided that is configured to monitor
control signaling between the lower layer protocol engine and the
upper layer application processing component. A communications
broker is provided that has a data buffer and defines a switchable
data path for user data between the upper layer application
processing component and a selected one of the wireless interfaces.
Preferably, the application broker is associated with the
communications broker to control data buffering and data path
switching by the communications broker such that data flowing to a
first wireless interface of the protocol engine during a
communication session is buffered while a wireless link is
established with a different second wireless interface of the
protocol engine for the communication session and the communication
broker data path is switched to the second wireless interface and
the buffered data is released therethrough after a wireless link is
established for the communication session via the second wireless
interface.
[0022] In one embodiment, the communication broker data path is
configured to transport packet switched data and a data path is
defined for circuit switch data between the upper layer application
processing component and a UMTS wireless interface. However, this
is not a limiting criteria.
[0023] Preferably, the application broker includes a link monitor
and is configured to trigger the initiation of a wireless link
through a different wireless interface based upon monitored link
data meeting predetermined criteria. The application broker can
also include an Application Session Manager configured to controls
the signaling during the establishment of a wireless link through a
different wireless interface and an inter-working unit configured
to maintain and convert context information for transmission during
the establishment of a wireless link through a different wireless
interface. Additionally, the application broker can include a
Subscriber Identity Module (SIM) reader configured to read a SIM
containing the user's identity.
[0024] A preferred wireless link handover method is provided for a
wireless transmit/receive unit (WTRU) for switching a wireless link
from a first to a second type of wireless network during a
communication session wherein the WTRU has a protocol engine having
first and second wireless communication interface configured for
wireless linking with the first and second types of wireless
networks, respectively, each communication interface configured to
pass control signals and user communication data to a common
application processing component. A data buffer and a switchable
data path for user data between the upper layer application
processing component and a selected one of the wireless interfaces
are provided. Control signaling is monitored between the lower
layer protocol engine and the upper layer application processing
component. The data buffer and data path switching are controlled
such that data flowing to the first wireless interface of the
protocol engine during the communication session is buffered while
a wireless link is established with the second wireless interface
of the protocol engine for the communication session and the data
path is switched to the second wireless interface and the buffered
data is released therethrough after a wireless link is established
for the communication session via the second wireless
interface.
[0025] Other objects and advantages of the present invention will
be apparent to persons skilled in the art from the following
description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1a is a schematic diagram of a typical UMTS system in
accordance with current 3GPP specifications.
[0027] FIG. 1b illustrates an example of a mobile WTRU operating in
different networks as it travels from a home WLAN to an office LAN
while maintaining a continuous communication in accordance with the
teachings of the present invention.
[0028] FIG. 2a is a block diagram of a multi-network enabled WTRU
in accordance with the teachings of the present invention.
[0029] FIG. 2b is an illustration of a multi-network interface of a
multi-network enabled WTRU in accordance with the teachings of the
present invention.
[0030] FIG. 2c is a process diagram illustrating the switching of a
communication session from a wireless connection via a WLAN to a
wireless connection via a UMTS without loss of connectivity in
accordance with the teachings of the present invention.
[0031] FIG. 3 is an illustration of a multi-network operating
environment for a multi-network enabled WTRU in accordance with the
teachings of the present invention.
[0032] FIG. 4a is a layout diagram of a UMTS device architecture
design configured to interface with a computing device, such as via
a standard PCMCIA/HBA interface,
[0033] FIG. 4b is a layout diagram of dual UMTS/WLAN network device
architecture design configured to interface with a computing
device, such as via a standard PCMCIA/HBA interface, in accordance
with the teachings of the present invention.
[0034] FIG. 5a is a block diagram of a preferred example of
functionality details of an Application broker component for a WTRU
in accordance with the teachings of the present invention.
[0035] FIG. 5b is a block diagram of a preferred example of
functionality details of a Communication broker component for a
WTRU in accordance with the teachings of the present invention.
[0036] FIG. 6a is a protocol stack diagram illustrating preferred
locations of the operation of the inventive components in the UE,
UTRAN and SGSN in a 3GPP context.
[0037] FIG. 6b is a protocol stack diagram illustrating preferred
locations of the operation of the inventive components in a WLAN
context.
[0038] FIG. 7 is a diagrammatic illustration of the location of the
inventive components for operation with a WIN CE context.
TABLE-US-00001 TABLE OF ACRONYMS 2G Second Generation 2.5G Second
Generation Revision 3GPP Third Generation Partnership Project AAA
Authentication, Authorization and Accounting AAL2 ATM Adaptation
Layer Type 2 AAL5 ATM Adaptation Layer Type 5 AMR A type of voice
data compression AP Access Point (base station in WLAN) APP
Applications broker AS Access Stratum ASIC Application Specific
Integrated Circuit ATM Asynchronous Transfer Mode CDMA Code
Division Multiple Access CN Core Network CODECs Coder/Decoders COM
Communications broker CP Control Plane CS Circuit Switched ETSI
European Telecommunications Standard Institute ETSI SMG ETSI -
Special Mobile Group FA Forwarding Address FN Foreign Network G.729
A type of voice data compression GGSN Gateway GPRS Support Node GMM
GPRS Mobility Management GMSC Gateway Mobile Switching Center GPRS
General Packet Radio Service GSM Global System for Mobile
Telecommunications GTP GPRS Tunneling Protocol GW Gateway H.323/SIP
H.323 Format for a Session Initiated Protocol HLR Home Location
Register HN Home Network HSS Home Service Server IETF Internet
Engineering Task Force IP Internet Protocol ISDN Integrated
Services Digital Network ISP Internet Service Provider Iu-CS Iu sub
Interface for Circuit Switched service Iu-PS Iu sub Interface for
Packet Switched service IWU Inter Working Unit L1C Level 1 Control
LLC Logical Link Control (WLAN) M3UA Message Transfer Part Level 3
SCCP SS7 Adaptation Layer MAC Medium Access Control MAP Mobile
Application Part MSC Mobile Switching Centre NAS Non Access Stratum
Node B Base station in UMTS NRT Non-Real Time PCM Pulse Code
Modulation PCMCIA PC Memory Card International Association
PCMCIA/HBA PC Memory Card International Association Host Bus
Adapter PDCP Packet Data Convergence Protocol PLMN Public Land
Mobile Network PPP Point-to-Point Protocol PS Packet Switched PSTN
Public Switch Telephone Network RANAP Radio Access Network
Application Part RAN IP Radio Access Network Internet Protocol RIP
GW RAN IP Gateway RLAN Radio Local Area Network RLC Radio Link
Control RNC Radio Network Controller RRC Radio Resource Control RT
Real Time SCCP/MTP Signaling Connection Control Part, Message
Transfer Part SGSN Serving GPRS Support Node SCTP Stream Control
Transmission Protocol SIM Subscriber Identity Module SM Session
Management SMS Short Message Service SS7 Signaling System 7 SSCF
Service Specific Coordination Function SSCOP Service Specific
Connection Oriented Protocol TCP Transmission Control Protocol TDD
Time Division Duplex UDP/IP User Data Protocol for the Internet
Protocol UE User Equipment (WTRU for UMTS) UICC UMTS Integrated
Circuit Card UMTS Universal Mobile Telecommunications System UP
User Plane UTRAN UMTS Terrestrial Radio Access Network WIN CE
Windows CE WLAN Wireless Local Area Network WTRU Wireless Transmit
Receive Unit VLR Visitor Location Register
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] The present invention is described with reference to the
drawing figures wherein like numerals represent like elements
throughout.
[0040] The term base station as used herein includes, but is not
limited to, a base station, Node B, site controller, Access Point
(AP) or other interfacing device in a wireless environment that
provides WTRUs with wireless access to a network with which the
base station is associated.
[0041] The term WTRU as used herein includes, but is not limited
to, a user equipment (UE), mobile station, fixed or mobile
subscriber unit, pager, or any other type of device capable of
operating in a wireless environment. WTRUs include personal
communication devices, such as phones, video phones, and Internet
ready phones that have network connections. In addition, WTRUs
include portable personal computing devices, such as PDAs and
notebook computers with wireless modems that have similar network
capabilities. WTRUs that are portable or can otherwise change
location are referred to as mobile units.
[0042] The present invention provides for continuous communication
sessions via differing types of wireless radio access networks
having one or more networked base stations through which wireless
access service is provided for WTRUs. The invention is particularly
useful when used in conjunction with mobile units, i.e., mobile
WTRUs, as they enter and/or travel through the respective areas of
geographic coverage provided by the respective base stations of
different types of networks. For example, FIG. 1b illustrates a
mobile WTRU 10 at three different locations 10a, 10b, 10c. At
location 10a, the WTRU conducts wireless communication with an AP
12 of a home WLAN. At location 10b, the WTRU conducts wireless
communication with a Node B 13 of UMTS while traveling between the
home WLAN and an office WLAN. At location 10c, the WTRU conducts
wireless communication with an AP 15 of an office WLAN. Network
connectivity is provided by connections of a CN 14 of the UMTS with
the home and office WLANs. The WTRU 10 of the present invention,
takes advantage of this network connectivity to maintain an ongoing
communication session initiated at the home WLAN 10a and continued
at the office WLAN 10c by switching between WLAN and UMTS wireless
communications while in transit 10c.
[0043] In accordance with the invention, WTRUs are configured for
at least two different network modes of operation, preferably, by
being equipped with devices providing UMTS UE functionality and
wireless local area network (WLAN) WTRU functionality, such as
802.11(b) (WiFi) or Bluetooth compliant functionality. However, the
proposed invention is applicable to provide continuity of
communication sessions for any other type of wireless network
system that interconnects with other types of networks.
[0044] Referring to FIG. 2, a WTRU 10 is provided with a protocol
engine 20 having at least two wireless communication interfaces 22,
24, of different types. Each communication interface 22,24 is
configured to pass control and user communication data to an
application processing component 26 representing conventional upper
layers of communication systems. Preferably, one of the wireless
communication interfaces 22, 24 is configured for UMTS wireless
communications and the other is configured for 802.11 WLAN
communications.
[0045] The invention provides for the interposition of an
Application broker (APP) 30 and a Communications broker (COM) 32
between the wireless interfaces 22, 24 and the upper layer
application processing component 26. The APP and COM components 30,
32 process the control and user data preferably as a type of
"middleware" that helps in inter-working different technologies by
abstracting the underlying base system to enhance performance
capabilities. The Application broker 30 and Communications broker
32 provide a two-tier middleware architecture that does not require
a change to conventional protocol architectures for the respective
wireless networks, easily integrate the different network
technologies and provide seamless service to the user.
[0046] The APP 30 is configured to monitor the control signaling
between the lower layer protocol engine 20 and the upper layer
application processing component 26. All user communication data
flows through the COM 32 which serves as a switch for the upper
layer application processing component 26 to direct such data to
the appropriate wireless interface 22, 24 within the lower layer
protocol engine 20.
[0047] The middleware components 30, 32 can be implemented in the
WTRU without corresponding network components. The APP 30 and the
COM 32 can operate in such a standalone WTRU scenario to maintain a
wireless communication session while switching networks. As such,
dual mode operation is supported in the WTRU without overall
network support and no "context transfer" or end to end "session
awareness" is required.
[0048] For example, if the WTRU 10 is conducting a UMTS wireless
communication via interface 22 and travels into a WLAN service area
the communication session is preferably switched to WLAN wireless
communication via interface 24 in a WTRU standalone mode as
follows. The protocol engine 20 provides link status information
which is received and evaluated by the APP 30 and a determination
is made to switch to WLAN wireless communications. This decision
can be based on Quality of Service (QoS) of the existing UMTS or
other factors such as disclosed in U.S. patent application Ser. No.
10/667,633 owned by the assignee of the present invention. After
the APP 30 determines the ongoing UMTS communication session should
be handed over to a WLAN, the APP 30 signals the COM 32 to prepare
for handoff and the COM 32 begins to buffer all communication data
being generated by the upper layer application processing component
26 for wireless transmission. Accordingly, the processing component
26 continues its generation of user data for the communication
session without interruption. The APP 30 communications to the
upper layer application processing component 26 that handoff is in
progress so that it can anticipate a delay in receiving wireless
data until the handoff is complete. The APP 30 then directs the
protocol engine 20 to establish a wireless WLAN connection via
interface 24 to which the UMTS communication session is to be
handed.
[0049] The protocol engine 20 signals the APP 30 when the WLAN
connection is established. The App 30 then signals handoff
completion to the COM 32 which in turn switches the direction of
the user communication data from the UMTS interface 22 to the WLAN
interface 24 and releases the buffered data to the WLAN interface
to update and continue the communication session. The APP also
signals handoff completion to the upper layer application
processing component 26 so the bi-direction user data for the
communication session continues traveling via the COM 32 and WLAN
interface 24. Finally, the APP 30 signals the protocol engine to
have the UMTS interface release the UMTS connection.
[0050] For enhanced operation, corresponding APP and COM components
can be provided in the networks with which the WTRU 10 is
communicating. FIG. 2b provides a schematic diagram of the layout
of the various components. Network system interfacing between UMTS
systems and WLAN systems are typically based on Packet Switched
(PS) data flows such as using an Internet Protocol (IP). FIG. 2b
illustrates a WTRU configured to permit network handoff for packet
switched IP sessions. CS voice signal data can pass through the APP
from the UMTS interface, but voice communications are possible to
implement in both a WLAN and a UMTS using a voice over IP protocol
where voice data is processed in packets.
[0051] As reflected in FIG. 2b, the APP 30 of WTRU 10 brokers the
signaling with the wireless interfaces 22, 24 between higher layers
and the COM 22. The WTRU 10 is configured to pass PS data to and
from the wireless interfaces 22, 24 through the COM 32. Preferably,
the UMTS and WLAN systems with which the WTRU communicates have
UTRANs and APs, respectively, configured with corresponding
Communication Brokers implemented above their respective physical
layer air interfaces as illustrated in FIG. 2b. A corresponding
Application broker is preferably provided in an IP node of the
network systems. The network side APPs and COMs provide network
support for inter-network handover.
[0052] In the context of the multi-network system illustrated in
FIG. 2b, an example of the WTRU 10 switching from a WLAN connection
to a UMTS connection during a communication session with network
support is illustrated in FIG. 2c. During an existing WLAN session,
control and user data pass through the WTRU's APP 30 and COM 32,
respectively, and over the WTRU's communication link via an AP of
the WLAN. The user data passing through the COM of the AP and the
control data passing to a network APP. When the communications link
reports data to the WTRU APP 30 based on which the APP determines
the link should be switched to a UMTS, the WTRU APP 30 signals the
WTRU COM 32 to begin buffering up link user communication data and
also signals the network APP which in turn signals the AP COM to
begin buffering down link user communication data. The WTRU COM 32
also preferably stores contest information related to the user
data, notes the last down link packet received from the AP and
identifies the last received down link packet to the WTRU APP 30.
The WTRU APP 30 then directs the WTRU interface to set up a UMTS
link. Provided a UMTS link is available, it is set up and the WTRU
link via a UMTS UTRAN is confirmed to the WTRU APP 30. The WTRU APP
30 then confirms this to the WTRU COM 32 and preferably signals to
the network APP via the UMTS connection context information
including AAA and QoS information. The WTRU COM 32 also preferably
signals context in formation relate to the user communication data
to the UTRAN COM. The WTRU APP 30 also signals the network APP the
identity of the last received downlink packet with a request to
resume communications which in turn is signaled by the network APP
to the AP COM. The AP COM releases the buffered downlink data to
the UTRAN COM preferably starting with the next successive packet
following the packet identified as last received downlink packet.
The buffered data is then exchanged via the UMTS connection through
the WTRU COM 32 and the UTRAN COMM. The communication then
continues as normal via the UMTS connection.
[0053] With reference to FIG. 3, a block diagram of the WTRU 10 in
the context of a multi-network environment which includes internet
connectivity. The WLAN network includes an Access Point (AP)
connected to a WLAN Gateway that has an associated WLAN AAA
tracking component. The UMTS includes a UTRAN and AAA, SGSN and
GGSN Core Network components. The WLAN interfaces with the internet
through the WLAN Gateway and the UMTS interfaces with the internet
via the GGSN component of the UMTS CN. Preferably, there is an AAA
interface between the WLAN AAA and UMTS AAA components.
[0054] In the context of the multi-network system illustrated in
FIG. 3, an example of the WTRU 10 switching from a WLAN connection
to a UMTS connection during a communication session with an
internet connected device 40 proceeds as follows. When the
communications link status indicates to the WTRU APP 30 that the
link should be switched to a WLAN link, the WTRU APP 30 signals the
WTRU COM 32 to begin buffering up link user communication data. The
WTRU COM 32 also preferably stores contest information related to
the user data, notes the last down link packet received from the
UTRAN and identifies the last received down link packet to the WTRU
APP 30. The WTRU APP 30 then receives AAA context information from
the UMTS AAA control and directs the WTRU interface to set up a
UMTS link. A WLAN link is set up and the WTRU link via a WLAN UTRAN
is confirmed to the WTRU APP 30. The WTRU APP 30 then confirms
establishment of the WLAN link to the WTRU COM 32 and preferably
also appropriately converts the AAA context data and signals it to
the WLAN AAA component. The WTRU COM 32 then releases the buffered
uplink data to the internet connected device 40. The communication
then continues as normal between the WTRU 10 and the internet
connected device 40 via the WLAN connection.
[0055] Referring to FIGS. 4a and 4b, there is shown an
implementation of the APP and COM components device configured to
interface with a computing device, such as via a standard
PCMCIA/HBA interface. FIG. 4a illustrates a layout diagram of a
UMTS device architecture design configured to interface with a
computing device, such as via a standard PCMCIA/HBA interface. Non
Access Stratum (NAS), Access Stratum (AS), Layer 1 Control (L1C)
and physical layer (Layer 1) components are illustrated with data
paths of control signals and user data, including both packet
switched (PS) and circuit switched (CS) data paths. The NAS layer
is coupled to a standard computer interface for coupling via a
standard PCMCIA/HBA interface connector.
[0056] FIG. 4b illustrates a modification of the device of FIG. 4a
to provide a dual UMTS/WLAN network device architecture in
accordance with the teachings of the present invention. An
Application broker 30 is disposed in the control signal path
between the NAS layer and the computer interface. A Communications
broker 32 that is coupled with the APP 30 is disposed in the PS
data path between the NAS layer and the computer interface. WLAN
interface components are provided preferably including an 802.11
compliant physical layer, Layer 1 Control components and 802.11
compliant Medium Access Control (MAC) and Logical Link Control
(LLC) components. The Medium Access Control (MAC) and Logical Link
Control (LLC) components have a control signal path coupled with
the APP 30 and a PS data path coupled with the COM 32.
[0057] Preferred detailed configuration layouts of the APP 30 and
COM 32 components are illustrated in FIGS. 5a and 5b, respectively.
The APP 30 preferably includes a communication module coupled with
a central processing unit. The communication module has external
connections for the couplings with the higher layer processing
(application), the WLAN interface via LLC control (LLC), the UMTS
interface via NAS level control (NAS) and the COM 32 (COM). An L1
connection is also directly provided to the physical layer to
assist in the monitoring of link status.
[0058] The APP 30 preferably includes Link Monitor, Application
Session Manager, Inter-Working Unit and Subscriber Identity Module
(SIM) Reader components associated with its central processing
unit. The Link Monitor component is configured to monitor link
status and to trigger hand off from one type of wireless network
link to the other if selected criteria are net. The Application
Session Manager is configured to controls the signaling during
handoff. The Inter-Working Unit is configured to maintain and
convert AAA, QoS profile and other context information for
transmission during handoff. The SIM Reader is configured to read a
SIM containing the user's identity for AAA functioning.
[0059] The COM 32 is preferably configured with a Control
component, a Switch/Buffer device and a read/write (R/W) device.
The control component is configured to control the switching of the
PS-data flow between the UMTS and WLAN interfaces depending upon
the type of wireless connection and has a connection coupled with
the APP 30 for receiving control signals. The Switch/Buffer and R/W
devices are disposed in the PS data path between the two interfaces
and the higher layer processing. The Switch/Buffer has a WLAN
connection (LLC) and a UMTS connection (PS) and the PS data flow is
through one or the other connection as controlled by the Control
component. The Switch/Buffer and R/W devices are to interrupt the
data flow from the high layer connection (IP Data) and buffer the
data received during handover and then release the buffered data
once the new network connection is established and the data path is
switched by the Control component.
[0060] For completeness, FIGS. 6a and 6b are provided to illustrate
the preferred WTRU and network locations of the APP and COM in UMTS
and WLAN protocol stacks respectively. FIG. 6a illustrate the APP
within the Control Plane (CP) protocol stacks and the COM within
the User Plane (UP) protocol stacks of a UMTS network. FIG. 6b
illustrates the APP and COM locations in WLAN protocol stacks for
the WTRU, a WLAN AP and a WLAN gateway configured with a 802.11
compliant wireless interface and a 802.3 intra-WLAN interface.
[0061] The ability to create UMTS and WLAN (standard 802.11)
inter-working is the culmination of an evolution path comprising
the steps of roaming, handoff, and seamless handoff, ending in the
present dual mode WTRU. Network interface strategies are addressed
in the 3GPP Technical Report TR 23.934. The present invention
addresses the seamless handoff situation providing an architecture
that supports seamless handoff with no coupling, or loose coupling,
or tight coupling scenarios.
[0062] The new APP and COM components can be extended to integrate
any access technology. FIG. 7 is a diagrammatic illustration of the
location of these components in a dual wireless interface device
(UE+WLAN Engine) such as illustrated in FIG. 4b for operation
within a WIN CE context.
[0063] Exemplary attributes of the COM broker include ability to
abstract the transport mechanism to upper layers. Although
described above for PS data, the COM, being on the user plane can
be implemented to routes user data in the form of CS and/or PS data
depending on the current system to which is attached. From a UMTS
point of view the COM component preferably resides on top of
PDCP/RLC/MAC/PHY protocols. The COM can be implemented as a generic
software component which can be adapted to any access
technology.
[0064] Exemplary attributes of the Access Broker (APP) include the
ability to abstracts all applications at session and presentation
layers. The APP preferably resides on the signaling (control) plane
(CP), collects reports of link quality and has the ability to
triggering handoff and assists in session re-establishment.
[0065] Preferably, the APP and COM components are implemented on an
single integrated circuit, such as an application specific
integrated circuit (ASIC) which may also include the UMTS and WLAN
interface components. However, portions of the processing
components may also be readily implemented on multiple separate
integrated circuits.
[0066] WTRU configurations and methods have been described for use
with UMTS and WLAN systems. However, the present invention can be
implemented for any wireless communications network system where
the WTRUs are configured to communicate with multiple types of
wireless networks.
* * * * *