Patent ID: 8270372

Claim:
A method for performing an inter-radio access technology (“Inter-RAT”) handover procedure, the method comprising: establishing a packet-switched (PS) service between a wireless device and a first RAT system; receiving a network directed handover command message from the first RAT system, wherein the network directed handover command message includes circuit-switched radio access bearer (CS RAB) configuration information for a second RAT system but does not include single radio voice call continuity (SRVCC) related information; determining, based on the presence of CS RAB configuration information, that an SRVCC handover procedure should be performed; and performing the SRVCC handover procedure from the first RAT system to the second RAT system by switching transfer of data from a PS radio access bearer of the PS service in the first RAT system to a CS RAB in the second RAT system, wherein the CS RAB is included in the CS RAB configuration information.