Improving TCP Throughput in 802.11 WLANs with High Delay Variability

Reduced throughput of TCP over wireless networks is mainly due to misinterpretation of wireless losses as congestion signals and high delay variability because of fluctuating radio channel quality. High delay variability often leads to spurious TCP timeouts which result in severe throughput degradation. In this paper, we show the negative impact of large delay variations in a mixed wired and 802.11 network scenario with bursty errors, and propose an adaptive algorithm that adds delay to packets in order to prevent spurious timeouts. Our algorithm can adjust to specific network characteristics such as propagation delays, loss rate, and number of mobile nodes, and is applied at the access point of a wireless LAN