Domain transferring method for single radio voice call continuity

• US 8,180,347 B2
• Filed: 12/31/2008
• Issued: 05/15/2012
• Est. Priority Date: 02/05/2008
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: You, Shilin, Cai, Jiyan, Hao, Zhenwu, Yu, Zhiming
• Primary Examiner(s): Bhattacharya, Sam
• Application Number:
  US12/866,202
• Publication Number:
  US 20110009120A1
• Time in Patent Office: 1,231 Days
• Field of Search: 455/404.1, 455/436, 455/437, 455/439, 455/442, 370/331
• US Class Current: 455/436
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1083 In-session procedures
• CPC Class Codes: H04L 65/1095 Inter-network session transfer or sharing
• CPC Class Codes: H04L 65/1096 Supplementary features, e.g. call forwarding or call holding systems providing special services or facilities to telephony subscribers H04M3/42
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
• CPC Class Codes: H04W 36/00226 wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]

Abstract

A domain transferring method for the single radio voice call continuity, a UE accesses via an LTE/SAE network, and sets up an IMS session anchored at a VCC AS with a remote node; when an S-IWF receives a handover request used to transfer the session to make the session access from a CS domain, the method comprises: the LTE/SAE network sends a handover command to the UE, the UE sends a handover complete message to a target access device after receiving the handover command; after the UE sends the handover complete message, or after the S-IWF receives the handover complete message, a release session notification message is sent to a VCC AS; after receiving the session release notification message, the VCC AS releases the session resources of the session.

Claims

1. A domain transferring method for single radio voice call continuity, a UE accessing via a long term evolution (LTE)/system architecture evolution (SAE) network, and setting up an IP multimedia subsystem (IMS) session with a remote node, and the session being anchored at a voice call continuity application server (VCC AS);

after an shared inter working function (S-IWF) receives a handover request which is sent by the LTE/SAE network and used to transfer the session to make the session access from a circuit switched (CS) domain, the method including;

the LTE/SAE network sending a handover command to the UE;

after receiving the handover command, the UE sending a handover completed message to a target access equipment in the CS domain;

after the UE sends the handover completed message, or after an S-IWF receives a message sent by the UE which indicates that the handover is completed, a release session notification message being sent to the VCC AS; and

after receiving the release session notification message, the VCC AS releasing session resources of the session from the VCC AS to the LTE/SAE network.

2. The method according to claim 1, wherein

after the S-IWF receives the handover request sent by the LTE/SAE network, and before the LTE/SAE network sends the handover command to the UE, the method also including:

the S-IWF sending the VCC AS a VCC transfer request including a VCC Domain Transfer Number (VDN);

the VDN being used to indicate the VCC AS to perform a single radio voice call continuity (SR VCC) domain transfer; and

the VCC AS learning from the VDN that it needs to release session resources of the session from the VCC AS to the LTE/SAE network only after receiving the release session notification message.

3. The method according to claim 1, wherein

after the S-IWF receives the transfer request sent by the LTE/SAE network, and before the LTE/SAE network sends the transfer command to the UE, the method also including:

before sending a VCC transfer request to the VCC AS to indicate the VCC AS to perform a VCC domain transfer, the S-IWF sending a transfer notification message to the VCC AS, to notify the VCC AS that an SR VCC domain transfer is about to be performed; and

the VCC AS learning from the transfer notification message that it needs to release session resources of the session from the VCC AS to the LTE/SAE network only after receiving the release session notification message.

4. The method according to claim 3, wherein

the transfer notification message is an unstructured supplementary service data (USSD) message, or a “

MESSAGE”

message of session initial protocol (SIP).

5. The method according to claim 1, wherein

the release session notification message is a USSD message, or a SIP indication message including a SIP-MESSAGE message, or a SIP INVITE message, or a SIP re-INVITE message.

6. The method according to claim 1, wherein

after receiving the release session notification message, the VCC AS also releases the session resources of the session of the LTE/SAE network and updates the remote bearer of the session.

10. The method according to claim 1, wherein

the notification message which indicates that the handover is completed is a USSD message or a SIP message.

7. A domain transferring method for single radio voice call continuity, a UE accessing via an LTE/SAE network, and setting up an IMS session with a remote node and the session being anchored at a VCC AS;

after an inter working function (IWF) receives a call setup message including a VDN which is sent by the UE, and a handover request which is sent by the LTE/SAE network and used to transfer the session to make the session access from a CS domain, the IWF controlling the LTE/SAE network and CS domain network to perform the subsequent handover operations, the method including;

after receiving a handover completed message sent by the LTE/SAE network, the UE sending a handover access message and a handover completed message to a target access equipment in the CS domain, and sending the VCC AS a notification message which indicates that a handover is completed; and

after receiving the notification message which indicates that the handover is completed, the VCC AS releasing the session resources of the session from the VCC AS to the LTE/SAE network.

8. The method according to claim 7, wherein

the VDN is used to indicate the VCC AS to perform a domain transferring of single radio voice call continuity;

after the IWF receives the handover request sent by the LTE/SAE network, and before the session resources of the session from the VCC AS to the LTE/SAE network are released, the method also including;

the IWF sending a call setup message including the VDN to a VMSC;

after receiving the call setup message, the VMSC sending an ISUP initial address message including the VDN to a media gateway control function (MGCF);

after receiving the ISUP initial address message, the MGCF setting up a SIP session with the VCC AS using the VDN; and

the VCC AS learning from the VDN that it needs to releases the session resources of the session from the VCC AS to the LTE/SAE network only after receiving the notification message which indicates that the handover is completed.

9. The method according to claim 7, wherein

after receiving the notification message which indicates that the handover is completed, the VCC AS also updates the remote bearer of the session.