A method for supporting backward compatibility of Multimedia Broadcast and
Multicast Service (hereinafter referred to as MBMS) in a mobile
communication system of Wideband Code Division Multiple Access
(hereinafter referred to as WCDMA) is disclosed. An example method
recites mapping relationship between the MBMS service identifier and the
RAB identifier and judging the capability of the RNC by the SGSN, and
accordingly, determining if the MBMS service is backwards compatible and
if user equipment is compatible with different versions.