TCP performance enhancement in Wireless networks using Cross layer approach

Abstract

Transmission Control Protocol TCP is a transport layer protocol newlinethat provides reliable data delivery and the reliability is achieved by newlineretransmission of lost packets The reliability of wired networks makes TCP newlineto assume any packet loss as an indication of congestion Wireless networks newlineare different from wired networks in terms of bandwidth propagation delay newlineand link reliability TCP suffers serious performance degradation in wireless newlinenetworks due to channel errors Spurious Retransmission Timeouts SRTOs newlineuser mobility and asymmetry The packets in transmission may be corrupted newlinein wireless channels leading to losses in TCP data segments or newlineAcknowledgements ACKs However TCP misinterprets non congestion newlinerelated packet losses as a sign of congestion and consequently invokes newlinecongestion control and avoidance procedures Thus the intermittent channel newlineerrors may cause the congestion window CWND size at the sender side to newlineremain small resulting in reduced TCP throughput The packet losses have to newlinebe differentiated between congestion and non congestion related losses newlineHowever differentiating the packet losses alone will not improve TCP newlinePerformance the presence of SRTOs caused by Spurious Timeouts and newlineSpurious Fast Retransmissions also affects TCP performance newlineThe user mobility causes hard and soft handoffs which in turn may newlinecause temporal link disconnections affecting the end to end path properties newline newline