Patent ID: 7522585
Filing Date: 2009-04-21
Classification: H04W

Abstract:
1. A method for handoff from a Packet Switched (PS) domain to a Circuit Switched (CS) domain comprising: when it is needed to handoff from the PS domain to the CS domain, a Mobile Station (MS) obtaining a handoff number and initiating a CS domain session to an Interworking Gateway (IWS) in a PS domain access network by taking the handoff number as a called number; the IWS directly delivering the CS domain session to a Mobile Switching Center (MSC) in the CS domain; an Interworking Gateway (IWGW) associating the CS domain session to an original session of the MS; the IWS notifying the MS to perform an air interface handoff from the PS domain to the CS domain; and the MS notifying the IWGW to finish the air interface handoff from the PS domain to the CS domain.