Method and Arrangement for Supporting Hand Over of a Mobile Terminal

• US 20130250032A1
• Filed: 03/23/2012
• Published: 09/26/2013
• Est. Priority Date: 03/23/2012
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Henrik Andre-Jonsson, Lena Melin
• Inventors: Andr-Jnsson, Henrik, Melin, Lena
• Granted Patent: US 9,119,116 B2
• Time in Patent Office: Days
• US Class Current: 348/14.02
• 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

Network nodes in a source and a target communication system, and methods therein for supporting hand over to the target communication system, of a mobile terminal supporting Packet Switched-to-Circuit Switched, PS-to-CS, hand over. The method in the source communication system comprises, when requesting resources for hand over of a mobile terminal engaged in a conversational call to a target node in the target communication system, signaling a first request for PS resources to the target communication system, indicating a bearer B, used for the conversational call, and further signaling a second request for CS resources to the target communication system, indicating the bearer B. Thereby, the target communication system is enabled to decide whether a PS-to-CS HO or a PSHO of the bearer B should be performed.

Claims

1. A method in a core network node in a packet switched (PS) first cellular communication system for supporting Hand Over (HO) to a target cellular communication system of a mobile terminal (UE) supporting PS-to-Circuit Switched (CS) HO, the method comprising:

when requesting resources for HO of a UE engaged in a conversational call to a target node in the target communication system;

signaling a first request for PS resources to the target communication system, indicating a bearer B used for the conversational call; and

signaling a second request for CS resources to the target communication system, indicating the bearer B, thus enabling the target communication system to decide whether a PS-to-CS HO or a PSHO of the bearer B should be performed.

2. The method of claim 1, further comprising:

receiving an indication from the target communication system, as a response to the first and second request;

determining whether to trigger a PS-to-CS HO or a PSHO of the bearer B to the target node, based on the received indication.

3. The method of claim 1, wherein all Radio Access Bearers (RABs) associated with the UE are indicated in the first request for PS resources.

4. The method of claim 1, wherein the conversational call is a Voice over Internet Protocol (VoIP) call anchored in the IP Multimedia Subsystem (IMS).

5. The method of claim 4, wherein the conversational call is a multimedia call also involving visual communication.

6. The method of claim 1, wherein the UE supports at least one of a Single Radio Voice Call Continuation (SRVCC) and a Single Radio Video Call Continuation (vSRVCC) type of PS-to-CS HO.

7. The method of claim 1, wherein the HO is an Inter Radio Access Technology (IRAT) HO.

8. A network node operable in a packet switched (PS) cellular communication system, for supporting Hand Over (HO) to a target cellular communication system of a mobile terminal (UE) supporting PS-to-Circuit Switched (CS) HO, the network node comprising:

a signaling unit configured to, when requesting resources for HO of a UE engaged in a conversational call to a target node in the target communication system, signal a first request for PS resources to the target communication system, indicating a bearer B, used for the conversational call, and further signal a second request for CS resources to the target communication system, indicating the bearer B.

9. The network node of claim 8, further comprising:

a receiving unit configured to receive an indication from the target communication system, as a response to the first and second request; and

a determining unit configured to determine whether to trigger a PS-to-CSHO or a PSHO of the bearer B to the target node, based on the received indication.

10. The network node of claim 8, wherein the HO is an Inter Radio Access Technology (IRAT) HO.

11. The network node of claim 8, wherein all Radio Access Bearers (RABs) associated with the UE are indicated in the first request for PS resources.

12. The network node of claim 8, wherein the conversational call is a Voice over Internet Protocol (VoIP) call anchored in the IP Multimedia Subsystem (IMS).

13. The network node of claim 12, wherein the conversational call is a multimedia call also involving visual communication.

14. The network node of claim 8, wherein the UE supports at least one of a Single Radio Voice Call Continuation (SRVCC) and a Single Radio Video Call Continuation (vSRVCC) type of PS-to-CS HO.

15. A method in a target network node in a cellular communication system for supporting Hand Over (HO) of a mobile terminal (UE) that supports Packet Switched to Circuit Switched (PS-to-CS) HO, wherein the network node supports both CS and PS communication and the method comprises:

receiving a first and a second request for resources for HO of a bearer B, from a source communication system, wherein one of the first and second request is related to CSHO and the other to PSHO; and

deciding whether to accept the request related to CSHO or the request related to PSHO based on a criterion related to capabilities of the network node.

16. The method of claim 15, further comprising indicating the decided type of HO to the source communication system.

17. The method of claim 15, wherein the criterion is related to whether the target network node supports VoIP anchored in the IP Multimedia Subsystem, IMS, and/or related to the load on the target node.

18. The method of claim 15, wherein the UE supports at least one of a Single Radio Voice Call Continuation (SRVCC) and a Single Radio Video Call Continuation (vSRVCC) type of PS-to-CS HO.

19. A network node for supporting Hand Over (HO) of a mobile terminal (UE) to the network node, the UE supporting Packet Switched to Circuit Switched (PS-to-CS) HO, wherein the network node is operable to be a target network node in a cellular communication system and supports both CS and PS communication, and wherein the network node comprises:

a receiving unit, configured to receive a first and a second request for resources for HO of a bearer B, from a source communication system, wherein one of the first and second request is related to CSHO and the other to PSHO; and

a deciding unit, configured to decide whether to accept the request related to CSHO or the request related to PSHO, based on a criterion related to capabilities of the network node.

20. The network node of claim 19, further comprising an indicating unit configured to indicate the decided type of HO to the source communication system.

21. The network node of claim 19, wherein the criterion is related to at least one of:

whether the network node supports VoIP anchored in the IP Multimedia Subsystem (IMS), and the load on the network node.

22. The network node of claim 19, wherein the UE supports at least one of a Single Radio Voice Call Continuation (SRVCC) and a Single Radio Video Call Continuation (vSRVCC) type of PS-to-CS HO.

23. A computer readable medium storing a computer program comprising program instructions for execution by a processor in a network node in a packet switched (PS) first cellular communication system that supports Hand Over (HO) to a target cellular communication system of a mobile terminal (UE) supporting PS-to-Circuit Switched (CS) HO, said program instructions configured to cause said network node to:

when requesting resources for HO of a UE engaged in a conversational call to a target node in the target communication system;

signal a first request for PS resources to the target communication system, indicating a bearer B, used for the conversational call; and

signal a second request for CS resources to the target communication system, indicating the bearer B, thus enabling the target communication system to decide whether a PS-to-CS HO or a PSHO of the bearer B should be performed.

24. A computer readable medium storing a computer program comprising program instructions for execution by a processor in a target network node in a cellular communication system, to support Hand Over (HO) of a mobile terminal (UE) that supports Packet Switched to Circuit Switched (PS-to-CS) HO, said program instructions configured to cause the target network node to:

receive a first and a second request for resources for HO of a bearer B from a source communication system, wherein one of the first and second request is related to CSHO and the other to PSHO; and

decide whether to accept the request related to CSHO or the request related to PSHO based on a criterion related to capabilities of the network node.