Methods and apparatuses for single radio voice call continuity (SRVCC) from CS to LTE

摘要

A method for a call control node (MSC Server) enhanced for Single Radio Voice Call Continuity (SRVCC) allowing for a session transfer of a call involving a User Equipment (UE) of a handover party from a circuit switched (CS) access towards a target packet switched (PS) access is provided, the call involving said handover party and another party, said call being anchored in an Service Centralization and Continuity Application Server (SCC AS) of the IP-Multimedia-Subsystem (IMS), the method comprising the steps of receiving (202) an indication that the User Equipment (UE) is SRVCC capable, receiving (204) an indication of an address and port the UE is going to use for speech media over PS, providing (206) the UE with an indication of the address and port to be used towards the other party (remote end), deciding (208) to perform a SRVCC from CS access to said target PS access, sending (210) a relocation request for a bearer to a respective mobility management node (SGSN/MME), including said address and said port of the UE to be used for creating a PDP context, and sending (212) a handover command message to the UE, sending (214) a request for a “Forward Session Transfer” to the SCC AS, using the address and the allocated port to be used for media to construct a respective SDP.

主权项

1. A method implemented by a call control node enhanced for Single Radio Voice Call Continuity (SRVCC) for allowing a session transfer of a call involving a User Equipment (UE) of a handover party from a circuit switched (CS) access towards a target packet switched (PS) access, the call involving said handover party and another party, said call being anchored in an Service Centralization and Continuity Application Server (SCC AS) of an IP-Multimedia-Subsystem (IMS), the method comprising:
receiving at the call control node an indication that the UE is SRVCC capable, wherein the call control node is in a core network for said CS access; receiving at the call control node an indication of an address and port the UE is going to use for speech media over PS access; providing the UE with an indication of an address and port of the other party; deciding at the call control node to perform a SRVCC from said CS access to said target PS access; sending a relocation request for a bearer from the call control node to a respective mobility management node, said relocation request including said address and said port of the UE, to be used for creating a PDP context, wherein said respective mobility management node is either in the core network for said CS access or in a core network for said target PS access, sending from the call control node to the UE a handover command message that indicates CS to PS handover shall occur, and sending a request for a Forward Session Transfer from the call control node to the SCC AS, using the address and the port the UE is going to use for speech media over PS access to construct a respective Session Description Protocol (SDP).