Patent ID: 7839809

Claim:
A method for ensuring multicast service continuity in a radio communications system comprising a core network ( 20 ) and at least two radio network controllers ( 3 , 14 , 15 , 21 , 22 ) connected to the core network, wherein each radio network controller has a first identifier of each of the multicast services for which activation was previously requested by at least one radio terminal ( 1 , 11 ) via said radio network controller and is adapted to notify radio terminals located in a coverage area of said radio network controller of the starting of at least one session relating to one of said multicast services, reported by the core network, the notification incorporating the first identifier of said service, wherein each radio network controller also has a second identifier of each of the multicast services for which activation was previously requested by at least one radio terminal via said radio network controller, the second identifier of each service being longer than the first identifier of the same service, the method comprising, with respect to a radio terminal ( 11 ) entering the coverage area of a drift radio network controller ( 15 ) after having been in the coverage area of a serving radio network controller ( 14 ) each being one of said radio network controllers, said radio terminal having previously requested activation of a multicast service via the serving radio network controller, a step of sending the first identifier of said service from the serving radio network controller to the drift radio network controller.