CIPHERING METHOD IN MOBILE COMMUNICATION SYSTEM OF SERVING MULTIMEDIA BROADCAST/MULTICAST SERVICE, FOR INFORMING OF USE START-TIME OF PARAMETERS USED FOR ENCRYPTION

摘要

PURPOSE: A ciphering method in a mobile communication system of serving a multimedia broadcast/multicast service is provided to perform stably an MBMS service by informing a mobile terminal of a start time when a ciphering key is used after providing the ciphering key to the mobile terminal. CONSTITUTION: A BM-SC(440) or one of components of a CN performs a service announcement(441). A BM-SC performs an authentication process(442). A BM-SC performs a ciphering process related to the UE(443). The BM-SC transmits a response message to the UE(400)(444) when the ciphering process is completed. The BM-SC transmits a session start message to a GGSN(430)(445). The GGSN transmits the session start message to a SGSN(420)(431). The SGSN transmits the session start message to a UTRAN(410)(421). An RNC connected to the UE transmits a notification message to the UE(412). The CN and the UTRAN transmit MBMS data and the UE receives the MBMS data(446). The BM-SC generates a new ciphering key(447).