A method ensures that a reduction in data throughput is minimized in the event of a cell change in a GPRS network. When it is determined that cell change is appropriate for a mobile station, the BSS ensures that no further data for the mobile station is transmitted form the SGSN, and then continues to transmit all buffered data to the mobile station. The throughput may be deliberately reduced for a part of this time, so that the system timers become adapted to the reduction in throughput which will occur at the cell change. When the buffer has been emptied, the cell change is effected and, thereafter, that mobile station is prioritised in the BSS, in order to allow any buffered data on the uplink or downlink to be cleared.