Patent ID: 8908643

Claim:
A method of handing over with Single Radio Voice Call Continuity, SRVCC, a priority call from a User Equipment, UE, accessing an IP Multimedia Subsystem, IMS, network via a Circuit Switched, CS, access network to a target Packet Switched, PS, access network thereby establishing a priority IMS session, wherein the priority call has a specified CS priority level, the method comprising: sending a handover request from the CS access network towards the PS access network and the IMS network to transfer the priority call, wherein the handover request is sent from the CS access network to a Mobile Switching Centre, MSC, server; determining a PS priority level for the priority IMS session in the PS network based on a mapping operation performed by the MSC server to determine the PS priority level based on the specified CS priority level; forwarding, from the MSC server, the handover request together with the determined PS priority level to the target PS network; sending an indication of the requested CS to PS handover with SRVCC together with the determined PS priority level to a Policy and Charging Rules Function, PCRF, network component to change the IMS signaling bearer resources to correspond to the PS priority level; allocating bearer resources for the priority IMS session, wherein the bearer resources are allocated in response to the PS priority level; and transferring the call to the priority IMS session over the PS access network.