Patent ID: 7616607

Claim:
A method of controlling a cell change in a mobile communications network, in which data is transmitted from a serving GPRS support node (SGSN) to a mobile station in packets, and in which data packets are stored in a respective radio access node before transmission to the mobile station, the method comprising: detecting a cell change of a mobile station, from a first cell served by a first cell radio access node to a second cell served by a second cell radio access node; sending a first message from the SGSN to the first cell radio access node in response to detecting a cell change of the mobile station, sending a reply message from the first cell radio access node to the SGSN, wherein the reply message comprises at least a copy of one of the data packets awaiting transmission to the mobile station and unable to be transferred to the second cell radio access node; discarding the at least one of the data packets in the first cell radio access node; and in response to said reply message, transmitting said copy of at least one of the data packets from the SGSN to the second cell radio access node.