Proactive-WTCP: an end-to-end mechanism to improve TCP performance over wireless links

Standard TCP suffers in the wireless environment due to channel errors and frequent temporary disconnections of the wireless link. To solve both problems, we propose an end-to-end scheme, proactive-WTCP, in this paper. It only modifies the mobile end. Link layer retransmission scheme is used to deal with the wireless packet corruption. Mobile host withholds the duplicate acknowledgements for a dynamically calculated period in order to allow link layer recovery. Mobile host deals with the temporary disconnections by forcing the TCP sender into the persist mode before disconnection. Acknowledgements sent upon reconnection makes TCP sender exit the persist mode and resume the transmission. We evaluate proactive-WTCP in wireless LAN and GPRS network scenarios using throughput and transfer delay as the performance metrics for comparison. The simulation results show the significant improvements over TCP New Reno and Snoop with multicasting techniques.