Patent ID: 9078173
Filing Date: 2015-07-07
Classification: H04W

Abstract:
1. A method for a handover from a circuit switched domain to a packet switched domain, the method comprising: receiving, by a target mobility management entity, a circuit switched domain (CS) to packet switched domain (PS) handover request message that corresponds to a user equipment (UE) and is from a mobile switching center (MSC); triggering, by the target mobility management entity and according to the CS to PS handover request message, setup of a dedicated voice over Internet protocol (VoIP) bearer that corresponds to the UE, wherein the dedicated VoIP bearer is established either between a serving gateway (SGW) and a media gateway (MGW) or between the SGW and a packet data network gateway (PGW); sending, by the target mobility management entity, a handover request message to a target access network to instruct the target access network to prepare a handover resource for the UE; sending, from the target mobility management entity to the MSC, a CS to PS handover response message corresponding to the UE, wherein the CS to PS handover response message carries the handover resource prepared by the target access network for the UE, so that the UE is handed over to the target access network using the handover resource, wherein the dedicated VoIP bearer is used to bear a VoIP session between the UE and the MGW after the UE is handed over to the target access network, and wherein the CS to PS handover request message further carries address information of the MGW; and sending, by the target mobility management entity, a create session message carrying the address information of the MGW to the SGW, wherein the create session message triggers establishment of a default bearer corresponding to the UE between the SGW and the MGW.