METHOD AND APPARATUS FOR INTER-TECHNOLOGY HANDOFF OF A TERMINATING MOBILE STATION DURING AN ALERTING PROCEDURE

摘要

A communication system (100) implements a handoff of a call that is to be anchored in an IMS network (150) and is initiated via a terminating packet data network (132) but is handed off to a terminating cellular, or circuit switched, network (142) during an alerting procedure. An originating mobile station (102) initiates a call to a terminating mobile station (104) via the terminating packet data network. Prior to the setup of the call, the terminating mobile station determines that a handoff to the terminating cellular network is desired. The terminating mobile station alerts a user of the terminating mobile station to the call and, while the call is answered and before completing the setup of the call, initiates a switching of the call from the terminating packet data network to the terminating cellular network. The call is then established with the terminating mobile station via the terminating cellular network.