Patent ID: 7177625

Claim:
A method for transmitting useful information of a multimedia broadcast/multicast service in a radio communication system with at least one radio network control device and at least one base station forming a base station subsystem, the radio network control device being connected to an access device of a core network and the at least one base station being connected to at least two user stations via a radio communication interface, said method comprising: holding a service-specific key, which is specific to the multimedia broadcast/multicast service and which includes authorization to use the multimedia broadcast/multicast service, by both the radio network control device and the at least two user stations, the service-specific key not including any specific information about the at least two user stations; receiving at the radio network control device a received key from at least one of the at least two user stations; and transmitting the useful information of the multimedia broadcast/multicast service to the at least one user station, only if a verification carried out by the radio network control device solely based on the received key shows that the received key corresponds to the service-specific key.