USER EQUIPMENT, CALL CONTINUITY APPLICATION SERVER, AND NETWORK HANDOVER METHOD

• US 20090147754A1
• Filed: 02/10/2009
• Published: 06/11/2009
• Est. Priority Date: 09/08/2006
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: XU, Jie, Long, Shuiping, ZHANG, Yi, YOU, Fang
• Granted Patent: US 8,155,084 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1095 Inter-network session transfer or sharing
• CPC Class Codes: H04M 3/428 Arrangements for placing incoming calls on hold
• CPC Class Codes: H04M 7/123 where the packet-switched network is an Internet Protocol Multimedia System-type network
• CPC Class Codes: H04W 36/00226 wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]
• CPC Class Codes: H04W 80/10 adapted for application session management, e.g. SIP [Session Initiation Protocol] connection management H04W76/00; arrangements for session management H04L67/14

Abstract

A network handover method applicable to network handover in ringing/ring back tone (RBT) or call hold is provided. According to this method, in ringing/RBT, one party performs a session negotiation with an Other End Point (OEP) via a call continuity application server, and then sends an off-hook signal to the OEP via the call continuity application server after the negotiation succeeds. Further, a call continuity application server and a user equipment (UE) are provided. According to the present disclosure, in ringing/RBT or call hold, even if the network coverage is not good, the UE may also be handed over to another network through call continuity, so as to effectively prevent the UE from dropping a call in ringing/RBT or call hold and thus improve the conversation quality of the user.

Claims

1. A method for a user equipment (UE) to perform network handover, comprising:

performing, by the UE that initiates a handover, a session negotiation on call continuity handover in a call-hold state with an Other End Point (OEP) via a target network; and

handing over a call to the target network after the session negotiation succeeds.

2. The method according to claim 1, wherein the UE performs the session negotiation with the OEP via a call continuity application server in the target network.

3. The method according to claim 2, further comprising:

sending, by the UE, a network handover request carrying session description information of the UE to the call continuity application server, wherein

the performing the session negotiation further comprises performing the session negotiation according to the session description information, and

the handing over the call to the target network after the session negotiation succeeds further comprises handing over a call corresponding to the network handover request to the target network after the session negotiation according to the session description information succeeds.

4. The method according to claim 3, wherein the session description information carries call-hold information of the UE that initiates the handover.

5. The method according to claim 3, wherein a network to be handed over by the UE that initiates the handover is a circuit switched (CS) network, wherein the target network is an IP multimedia subsystem (IMS) network, and wherein the performing, by the UE that initiates the handover, the call-hold session negotiation with the OEP via the call continuity application server in the target network further comprises:

sending, by the UE that initiates the handover, the network handover request carrying session description information of the UE to the call continuity application server via the IMS network.

6. The method according to claim 3, wherein a network to be handed over is an IMS network, and the target network is a circuit switched (CS) network, and

the performing, by the UE that initiates the handover, the call-hold session negotiation with the OEP via the call continuity application server in the target network further comprises:

sending, by the UE that initiates the handover, an INVITE message to the call continuity application server via the CS network, a mobile switching center (MSC), and a media gateway control function (MGCF), wherein the INVITE message contains session description information of the MGCF.

7. A network handover method of a user equipment (UE), comprising:

receiving a network handover request from the UE that initiates a handover, wherein the network handover request carries session description information of the UE;

if it is detected that a call is in a call-hold state, updating the session description information and sending the session description information carrying call-hold information of the UE that initiates the handover to an Other End Point (OEP); and

handing over the call to a target network according to the network handover request after a session negotiation of the UE with the OEP, by using the session description information, succeeds.

8. The method according to claim 7, further comprising:

receiving session description information carrying call-hold information of the OEP fed back from the OEP, and sending the session description information carrying the call-hold information of the OEP to the UE that initiates the handover.

9. The method according to claim 7, wherein the detected call-hold state is a call hold initiated by the UE that initiates the handover, and

the session description information of the UE is send-only (sendonly) session description information, and the session description information to the OEP is receive-only (recvonly) session description information.

10. The method according to claim 7, wherein the call-hold state detected by a call continuity application server is a call hold initiated by the OEP;

and

the session description information of the UE is receive-only (recvonly) session description information, and the session description information to the OEP is send-only (sendonly) session description information.

11. The method according to claim 9, wherein the recvonly session description information is added by the UE that initiates the handover or the call continuity application server.

12. The method according to any one of claims 7 to 10, further comprising:

releasing a call leg of a network to be handed over.

13. The method according to any one of claim 7, wherein the network to be handed over is an IP multimedia subsystem (IMS) network, and the target network is a circuit switched (CS) network;

an INVITE message sent by the UE that initiates the handover via the CS network and a mobile switching center (MSC) is received from a media gateway control function (MGCF), and the INVITE message contains session description information of the MGCF; and

the updating the session description information and sending the session description information carrying the call-hold information of the UE that initiates the handover to the OEP further comprises;

generating an UPDATE message of the session description information according to the INVITE message, and sending the INVITE or the UPDATE message that contains session description information carrying call-hold information of the MGCF to the OEP.

14. The method according to claim 13, wherein the detected call-hold state is a call hold initiated by the UE that initiates the handover;

wherein the session description information carrying the call-hold information of the MGCF is send-only (sendonly) session description information; and

wherein the session description information carrying the call-hold information of the OEP is receive-only (recvonly) session description information, further comprises;

synchronizing call-hold states of the UE that initiates the handover and the MSC after the session negotiation succeeds.

15. The method according to claim 13, wherein the detected call-hold state is a call hold initiated by the OEP;

wherein the session description information carrying the call-hold information of the MGCF is receive-only (recvonly) session description information; and

wherein the session description information carrying the call-hold information of the OEP is send-only (sendonly) session description information, further comprises;

synchronizing call-hold states of the call continuity application server and the CS network after the session negotiation succeeds.

16. A user equipment (UE), comprising:

a session negotiation processing unit adapted to perform a session negotiation on call continuity handover in a call-hold state with an Other End Point (OEP) via a target network; and

a call-hold call continuity handover unit, adapted to hand over a call to the target network after the session negotiation succeeds.

17. A call continuity application server, comprising:

a processing unit, adapted to perform a session negotiation for a handover to a target network in a call-hold state; and

a control unit adapted to control a call continuity network handover in a call-hold state after the session negotiation succeeds.

18. The call continuity application server according to claim 17, further comprising:

a releasing unit adapted to release a call leg in a network to be handed over after the session negotiation succeeds.