Patent ID: 7400584

Claim:
A method of controlling data transmission from a remote unit to a radio terminal via a cellular radio communication network including a plurality of base stations, a packet control unit capable of communicating with the terminal via at least two of the base stations, and a network sub-system to route data between the remote unit and the packet control unit, wherein at least some of the data transmitted by the remote unit to the terminal are stored temporarily in the packet control unit, the data stored temporarily containing Transmission Control Protocol (TCP) data segments, wherein the remote unit is arranged to receive from the terminal acknowledgments relating to transmitted TCP data segments and to retransmit TCP data segments that have not been acknowledged on expiry of a retransmission time depending on the received acknowledgments, the method comprising: transmitting data containing TCP data segments from the remote unit to the terminal via a first one of the base stations connected to the packet control unit; and in response to a request for communication transfer to a second one of the base stations connected to the packet control unit, retransmitting a portion of the data stored temporarily in the packet control unit to the terminal via the second base station, wherein the retransmitted portion of the data is less than all the data in the buffer, and encompasses at least one complete TCP data segment.