Patent ID: 8031597

Claim:
A packet data communication method carried out by an MS (mobile station) connected to a communication server over a mobile communication network, the method comprising: detecting an error having occurred in received packet data during communication in a radio network, and determining that a congestion window size should not be reduced if the error is detected by the MS in a lower layer associated with the radio network; requesting the communication server to retransmit the packet data without reducing the congestion window size if the error is detected by the MS in the lower layer associated with the radio network; detecting an error having occurred in received packet data during communication in a wireline network; and requesting the communication server to retransmit the packet data after reducing the congestion window size by not transmitting an acknowledgment message to the communication server, wherein the requesting of the communication server to retransmit the packet data without reducing the congestion window size comprises transmitting a dummy segment having a TCP header with a certain flag set, the dummy segment comprising a segment of 20 to 60 bytes without data.