Patent ID: 7546108

Claim:
A method for supporting backward compatibility of MBMS (Multimedia Broadcast and Multicast Service) comprising steps of: receiving a Session Start message from a GGSN (Gateway GPRS (General Packet Radio Service) Support Node) by a SGSN (Service GPRS Support Node) when the SGSN requires to send a MBMS data including a MBMS Session Start to a UE; receiving an Activate MBMS Context Request message from the UE by the SGSN and sending an Activate MBMS Context Accept message to the UE with the information exchange with the GGSN when the UE joins in the case of the MBMS session is in operation; receiving a Service Request message or a Routing Area Update message for the reason of MBMS Service from the UE by the SGSN when the UE move in with the MBMS session is in operation; judging whether an interested RNC (Radio Network Controller) supports the MBMS or not by the SGSN; sending the MBMS service to the interested UEs of the RNC in the mode of Re199 by the SGSN if the RNC cannot support the MBMS; and sending a RAB (Radio Access Bearer) Allocation Request message to the RNC by the SGSN to establish 1u user interface bearer for the UE, the RAB Allocation Request message contains a RAB identifier of the UE corresponding to the MBMS service.