HK1126611B - Method and apparatus for supporting circuit switched interworking - Google Patents

Description

Method and apparatus for supporting circuit switched interworking

Technical Field

The present invention relates to wireless communications, and more particularly to interworking between Internet Protocol (IP) multimedia core network subsystem (IMS) voice/video sessions and a combination of Circuit Switched (CS) calls and IMS sessions.

Background

The third generation partnership project (3GPP) is specifying how to combine Circuit Switched (CS) calls with IP multimedia core network subsystem (IMS) sessions and thus specifying interworking between such services and sessions. For 3GPP IMS voice/video sessions, and combinations of CS calls and IMS sessions, it is necessary to provide interworking therebetween.

Disclosure of Invention

The present invention is directed to enabling a dual mode terminal (WTRU) capable of supporting both Circuit Switched (CS) voice calls (e.g., global system for mobile communications (GSM)) and IMS multimedia sessions without interrupting the session/service. The present invention meets this increasing need for reliable GSM-based CS voice calls with the addition of multimedia services for which the need for such calls is increasing. In accordance with the present invention, when the two services are provided independently at the same time in one radio and combined at the other radio, such services are coordinated by providing a device that performs a circuit switched interworking function (CSIWF) in the IMS domain and enables combined CS and IMS sessions by interfacing with the CS and Packet Switched (PS) domains.

Drawings

The invention will be understood in more detail from the following description of preferred embodiments, given by way of example and understood in conjunction with the accompanying drawings, in which:

fig. 1 shows a signal flow diagram for a wireless call session with a combined CS and IMS session; and

figure 2 shows a signalling diagram for establishing a combined CS and IMS session between two wireless users.

Detailed Description

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone (without the other features and elements of the preferred embodiments) or in various combinations with or without other features and elements of the present invention.

When referred to hereafter, the terminology "wireless transmit/receive unit (WTRU)" includes but is not limited to a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a computer, or any other user device capable of operating in a wireless environment. Reference hereinafter to a "base station" includes, but is not limited to, a node B, a site controller, an Access Point (AP), or any other interfacing device in a wireless environment.

The present invention deals with terminating real-time sessions and calls taking into account different domains (CS, IMS) and different WTRU capabilities (CSI, IMS VoIP, etc.).

Briefly, the multimedia session is initiated from an IMS-only WTRU 12, where the invitation may include a voice component (V) and a media component (M) with corresponding attributes (see fig. 1 and 2). The receiving WTRU has a unique configuration, preferably a voice over GSM (CS domain) call. Then, once the IMS side 10b of the receiving WTRU10 accepts the multimedia call with its components, a CS voice bearer (bearer) is established between the calling user (the IMS capable WTRU 12) and the called user (the CS and IMS capable WTRU 10). In response to the voice (V) and multimedia (M) reply (OK) from the calling WTRU 12 via the IMS, the called WTRU10 responds with a Media Gateway (MGW)26 "calls" the called WTRU10, which establishes a CS voice call when the called WTRU10 responds. The MGW/MGWF 26 converts voice calls into a Voice over IP (VoIP) format. IMS CSIIWF 20 deliver media content to the IMS-enabled part of the CSI WTRU and support combined traffic (traffic) by means of the IMS domain.

Figure 1 shows a simplified signal flow diagram for a wireless call session between two network transceivers, namely a WTRU10 with Circuit Switched Interworking (CSI), i.e., CS and IMS capabilities, and a WTRU 12 with IMS capabilities, in order to control the establishment of a CS voice call in conjunction with an IMS multimedia session between the two terminals, one of which is IMS capable only, and the other of which is dual-mode (with both IMS and CS capabilities). WTRU10 has CS and IMS capable devices 10a and 10b, respectively, while WTRU 12 is IMS capable. The domain device 20 combines CS domain content with IMS domain content between the WTRU10, 12 entities in the manner described below. It should be noted that only two (2) WTRUs are shown in the example of fig. 1 for simplicity, but it should be understood that other WTRUs may participate in the combined session.

As shown in fig. 1, the IMS session signal S on the CSI WTRU assuming that the session has been established_IMSSent from the IMS client entity WTRU10 b and processed by the Radio Access Network (RAN)14, PS domain entity 18, and CSI interworking function (CSI IWF) entity 20, where it interacts with the CS signal S_SCAnd (4) combining. G_mIncluding the interface between the CSI IWF 20, which acts as a proxy call session control function (P-CSCF), and the IMS part 10b of the WTRU 10. The IWF 20 performs its functions using serving and Gateway GPRS Support Nodes (GGSNs) and (SGSNs), respectively, as described below.

CS signal S at CSI WTRU10 and from CS entity 10a_CSTo the RAN 14 and to the CS domain entity 16 via the Uu/Um radio interface. Uu is UTRAN (UMTS terrestrial radio Access network) and WTRU using CDMA and S in IMS domain_CSSession signal and IMS session signal S_IMSThe interfaces between the combined CSIIWF entities 20. Um is the air interface reference point for the 3GPP2 air interface. It is a wideband spread spectrum interface that uses CDMA (code division multiple access) technology and meets the evolving needs of 3G (third generation) systems and the current TAI (telecommunications industry association)/EIA (electronic industry association) 95-B standard.

Combined CS/IMS content signal S_V&MWill be transmitted bi-directionally between the two network transceivers, WTRUs 10 and 12, and may be implemented as CSI WF 20.

Referring to fig. 2, where like elements in fig. 1 and 2 are denoted by like numerals, a signaling sequence diagram between a CSI WTRU10 and an IMS WTRU 12 is shown.

In step S₁The IMS capable WTRU 12 initiates the combined session, thereby sending an "invite" to IMS domain a24a for the combined V and M sessions. The IMS domain is based on the Session Initiation Protocol (SIP), and the invite is a SIP message. At S₂The (V and M) "invite" is sent to the functional device 24B of IMS domain B. At S₃Device 24b forwards to a home (home) location register/home subscriber server (HLR-HSS)22 queries location and profile. Assume that WTRU10 has been previously S₀Powered on and has registered as a CSI capable WTRU and has been assigned (assign) IMS CSI IWF.

At S₄The HLR/HSS 22 provides the requested location and profile (with CSI capability) to the device 24b, which device 24b then at S₅Sending V to IMS CSI IWF 20&M "INVITE", and IMS CSIIWF 20 is at S₆The "invite" is sent to the IMS capable part 10 b.

At S₇WTRU10 receives the "invite" and at S₈Sending a 200 OK (V) to the IWF 20&M). At S₉The IWF 20 sends the OK to IMS Domain B, and IMS Domain B will be at S₁₀Forwarding the OK to IMS Domain A24a, and at S_10aStarting to establish CS and PS radio bearers B_CSAnd B_PSWhereby the procedure steps S are used for the IWF 20, the MGW/MGW26 and the CSI part 10a of the WTRU10, respectively_10b、S_10cAnd S_10d. At S11, IMS domain a24a sends an OK to WTRU 12. Establishing a CS voice bearer B between MGW/MGCF26 and CS part 10a_CS. And a PS voice bearer B is established between the IMS part 10B and the IMS domain B24B_PS。

At S₁₂The WTRU 12 acknowledges the OK and sends an ACK (V) to the IMS 24A&M), the IMS 24A is at S₁₃The ACK is sent to IMS 24B. At S₁₄IMS 24B will ACK (V)&M) to the IWF 20, the IWF 20 forwards only the ACK to the IMS part 10b of the WTRU10, and at S₁₆Only the ack (v) IM is forwarded to the MGW/MGCF 26.

At S₁₇The MGW/MGCF26 sends a ringing condition to the CS portion 10a of the WTRU10 to initiate the voice portion of the combined session. At S₁₈The CS 10a of the WTRU10 responds to the ringing. In step S₁₉The WTRU10 also acknowledges the ack (m) message.

CS Voice Call Session S₂₀Extending between the WTRU10 and the MGW/MGCF 26. At S₂₁The MGW/MGCF26 converts CS voice to Voice over IP (VoIP) format for transmission at S₂₂A VoIP session is provided between the MGW/MGCF26 and the IWF 20.

At S₂₃Media content is placed between the IWF 20 and the ISM portion 10b of the WTRU 10. At S₂₄The IWF 20 combines the converted CS voice (i.e., VoIP) with the media received from the WTRU10 and sends it to the WTRU 12 over the IMS domain 24A, at S₂₅The IMS domain may deliver the combined session to WTRU 12 and receive the combined session from WTRU 12. This combined session denoted Sc continues until the WTRU terminates the session, thus at S₂₆Sending a BYE (V) to IMS A24A&M), wherein the IMS A24A is at S₂₇The BYE is forwarded to the IWF 20. At S₂₈The IWF 20 sends BYE to the IMS portion 10a of the WTRU10 and at S₂₉The BYE is sent to the MGW/MGCF26, which is at S26₃₀The combined session is abandoned (release).

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments and each feature or element can be used in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium, examples of which include Read Only Memory (ROM), Random Access Memory (RAM), registers, buffer memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs), for execution by a general purpose computer or a processor.

For example, suitable processors include: a general-purpose processor, a special-purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any other type of integrated circuit, and/or a state machine.

A processor in association with software may be used to implement a radio frequency transceiver for use in a Wireless Transmit Receive Unit (WTRU), user equipment, terminal, base station, radio network controller, or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a video circuit, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a bluetooth module, a Frequency Modulated (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and/or any Wireless Local Area Network (WLAN) module.

Examples

1. A method in a wireless network having at least two users, comprising:

initially establishing a circuit-switched (CS) session between two users having different content capabilities;

establishing an IP Multimedia Subsystem (IMS) session between two users;

combining the CS session and the IMS session; and

interworking of combined CS and IMS sessions is provided.

2. The method of embodiment 1 wherein the content includes at least voice and multimedia.

3. The method of embodiments 1 and 2 wherein the first of the two users invites an IMS session.

4. The method of embodiments 1-3 wherein the second of the two users accepts the IMS invitation.

5. The method of embodiments 1-4 wherein the CS and IMS content is combined in the IMS domain using a CSI interworking function (IWF).

6. The method of embodiments 1-5, further comprising: one of the two users is configured as an Internet Protocol (IP) multimedia system (IMS) capable wireless transmit/receive unit (WTRU).

7. The method of embodiments 1-6, further comprising: one of the two users is configured as a wireless transmit/receive unit (WTRU) with interworking Internet Protocol (IP) multimedia system (IMS) and Circuit Switched (CS) call capabilities.

8. The method of embodiments 1-7, further comprising: the remaining one of the two users is configured as a wireless transmit/receive unit (WTRU) having interworking Internet Protocol (IP) multimedia system (IMS) and Circuit Switched (CS) call capabilities.

9. The method of embodiments 1-8, further comprising: an Internet Protocol (IP) multimedia system (IMS) capable WTRU initiates an invitation to a combined CS and IMS session.

10. The method of embodiments 1-9, further comprising: an interworking capable WTRU receives voice messages over CS capabilities and media content over IMS capabilities.

11. The method of embodiments 1-10, further comprising: an IMS-capable WTRU receives a voice over IP (VoIP) voice message combined with a media message through IMS capabilities.

12. The method of embodiments 1-11, further comprising: an interworking function is provided between the two users to receive media from the IMS capable WTRU and voice content in VoIP format and to provide media content to the IMS capability of the interworking WTRU and to convert the voice content in VoIP format to a format compatible with the CS capability of the interworking WTRU.

13. The method of embodiments 1-12, further comprising: an interworking function is provided between the two users to receive media and CS voice content from the interworking WTRU and provide the media content to the IMS capability of the IMS capable WTRU and convert the CS voice content to a VoIP format compatible with the IMS capability of the IMS capable WTRU.

14. The method of embodiments 1-13, further comprising: an interworking function (IWF) is provided between the two users to communicate an invitation from the IMS capable WTRU only to and to receive an acceptance from the interworking WTRU and to communicate the acceptance to the IMS capable WTRU through the IMS domain over which the invitation is communicated to the IWF.

15. The method of embodiments 1-14, further comprising: (IWF) establishing a CS voice bearer between a Media Gateway (MGW) in the IMS domain and CS capabilities of an interworking WTRU.

16. The method of embodiments 1-15, further comprising: (IWF) establishing a Packet Switched (PS) media bearer between the IMS capability of the interworking WTRU and an IMS domain.

17. An apparatus in a wireless network having at least two users, comprising:

means for initially establishing a circuit-switched (CS) session between two users having different content capabilities;

the apparatus also establishes an IP Multimedia Subsystem (IMS) session between two users by combining the CS session and the IMS session, thereby providing interworking of the combined CS and IMS sessions.

18. The apparatus of embodiment 17 wherein the content comprises at least voice and multimedia.

19. The apparatus of embodiments 17 and 18 wherein a first of the two users is configured to provide an invitation for an IMS session.

20. An apparatus as in embodiments 17-19, wherein a second of the two users is configured to respond to the invitation and send an acceptance of the IMS invitation.

21. The apparatus of embodiments 17-20, wherein the CS and IMS content are combined in the IMS domain using a CSI interworking function (IWF).

22. The apparatus of embodiments 17-21, further comprising: one of the two users is configured as an Internet Protocol (IP) multimedia system (IMS) capable wireless transmit/receive unit (WTRU).

23. The apparatus of embodiments 17-22, further comprising: one of the two users is configured as a wireless transmit/receive unit (WTRU) with interworking Internet Protocol (IP) multimedia system (IMS) and Circuit Switched (CS) call capabilities.

24. The apparatus of embodiments 17-23, further comprising: the remaining one of the two users is configured as a wireless transmit/receive unit (WTRU) having interworking Internet Protocol (IP) multimedia system (IMS) and Circuit Switched (CS) call capabilities.

25. The apparatus of embodiments 17-24, further comprising: an Internet Protocol (IP) multimedia system (IMS) capable WTRU is configured to initiate an invitation to a combined CS and IMS session.

26. The apparatus of embodiments 17-25, further comprising: an interworking capable WTRU is configured to receive voice messages over CS capabilities and media content over IMS capabilities.

27. The apparatus of embodiments 17-26, further comprising: an IMS-capable WTRU is configured to receive voice over IP (VoIP) voice messages combined with media messages through IMS capabilities.

28. The apparatus of embodiments 17-27, further comprising: providing an interworking function between the two users, the interworking function configured to receive media from the IMS-capable WTRU and VoIP-formatted voice content and to provide the media content to the IMS capabilities of the interworking WTRU, and configured to convert the VoIP-formatted voice content to a format compatible with the CS capabilities of the interworking WTRU.

29. The apparatus of embodiments 17-28, further comprising: an interworking function is provided between the two users, the interworking function configured to receive media and CS voice content from the interworking WTRU and provide the media content to the IMS capability of the IMS capable WTRU, and configured to convert the CS voice content to a VoIP format compatible with the IMS capability of the IMS capable WTRU.

30. The apparatus of embodiments 17-29, further comprising: an interworking function (IWF) is provided between the two users, the interworking function being configured to pass the invitation from the IMS capable WTRU only to the IMS capability of the interworking WTRU, and configured to receive an acceptance from the interworking WTRU and pass the acceptance to the IMS capable WTRU through the IMS domain, the invitation being passed to the IWF through the IMS domain.

31. The apparatus of embodiments 17-30, further comprising: (IWF) is configured to establish a CS voice bearer between a Media Gateway (MGW) in the IMS domain and CS capabilities of an interworking WTRU.

32. The apparatus of embodiments 17-31, further comprising: (IWF) configured to establish a Packet Switched (PS) media bearer between the IMS capability of the interworking WTRU and an IMS domain.

33. The apparatus of embodiments 17-32, further comprising: the (IWF) is configured to communicate a termination (BYE) message to the interworking WTRU and the MGW in response to the termination message from the IMS-capable WTRU.

34. The apparatus of embodiments 17-33, further comprising: the MGW is configured to provide an abandon call message to the interworking WTRU in response to the BYE message from the IWF.

35. A WTRU configured according to any one of embodiments 1-34.

36. A WTRU, wherein the WTRU is configured to operate any one of embodiments 1-34.

37. An interworking function (IWF), wherein the interworking function is configured according to any of embodiments 1-36.

38. An interworking function (IWF), wherein the interworking function is configured to operate any of embodiments 1-36.

Claims (13)

1. A method implemented in a circuit-switched interworking (CSI) interworking function (IWF) entity, the method comprising:

receiving circuit-switched (CS) voice call content from a first wireless transmit/receive unit (WTRU) via a Radio Access Network (RAN) and a circuit-switched (CS) domain entity;

receiving IP multimedia core network subsystem (IMS) session content from the first WTRU via the RAN and a Packet Switched (PS) domain entity;

generating combined IMS session content based on the CS voice call content and the IMS session content; and

sending the combined IMS session content to a second WTRU.

2. The method of claim 1, further comprising:

converting the CS voice call content to voice over Internet protocol (VoIP) content;

wherein the combined IMS session content includes the VoIP content.

3. The method of claim 1 wherein the combined IMS session content is sent to the second WTRU via an IMS domain.

4. The method of claim 1 wherein the combined IMS session content is sent to the second WTRU via a UMTS Terrestrial Radio Access Network (UTRAN).

5. The method of claim 1, wherein the CS voice call content is received via a network based on global system for mobile communications (GSM) or 3GPP2 Code Division Multiple Access (CDMA) technology.

6. An apparatus implemented in a circuit-switched interworking (CSI) interworking function (IWF) entity, the apparatus comprising:

means for receiving circuit-switched (CS) voice call content from a first wireless transmit/receive unit (WTRU) via a Radio Access Network (RAN) and a circuit-switched (CS) domain entity;

means for receiving IP multimedia core network subsystem (IMS) session content from the first WTRU via the RAN and a Packet Switched (PS) domain entity;

means for generating combined IMS session content based on the CS voice call content and the IMS session content; and

means for sending the combined IMS session content to a second WTRU.

7. The apparatus of claim 6, further comprising means for converting the CS voice call content to voice over internet protocol (VoIP) content, wherein the combined IMS session content includes the VoIP content.

8. The apparatus of claim 6, further comprising means for sending the combined IMS session content via an IMS domain.

9. The apparatus of claim 6, further comprising means for sending the combined IMS session content via a UMTS Terrestrial Radio Access Network (UTRAN).

10. The apparatus of claim 6, further comprising means for receiving the CS voice call content via a network based on global system for mobile communications (GSM) or 3GPP2 Code Division Multiple Access (CDMA) technology.

11. A method implemented in a circuit-switched interworking (CSI) interworking function (IWF) entity, the method comprising:

a CSI IWF entity receiving IP multimedia core network subsystem (IMS) session content from a first wireless transmit/receive unit (WTRU), the IMS session content including voice call content in an IMS domain and multimedia content in the IMS domain;

the CSI IWF entity converts the voice call content in the IMS domain into voice call content in a Circuit Switched (CS) domain;

a CSI IWF entity transmitting voice call content in a CS domain to a second WTRU via a CS domain entity and a Radio Access Network (RAN); and

a CSI IWF entity transmits multimedia content in the IMS domain to the second WTRU via a PS domain entity and the RAN.

12. The method of claim 11, wherein the voice call content is transmitted to the second WTRU via a network based on global system for mobile communications (GSM) or 3GPP2 Code Division Multiple Access (CDMA) technology.

13. The method of claim 11, wherein the voice call content in the IMS domain is in voice over internet protocol (VoIP) format.