Improving the performance of TCP over wireless networks

摘要

One of the major issues facing TCP (Transmission Control Protocol) when implemented in 802.11 wireless networks is that it doesn't adapt its RTO (retransmission timeout) to sudden large delays. Several times the usual RTT (Round Trip Time), i.e. RTO is reached before the sudden large delay passes leading to an early timeout and early retransmissions. Such delays can be caused by errors on wireless data links like shadowing, fading, noise, interference, etc. In this paper, we propose an end-to-end enhancement for the current TCP by dealing with sudden large delays in wireless networks caused by combined shadowing and path loss. This will be done through extending RTO dynamically using different methods in such a way that prevents early timeouts and early retransmissions due to shadowing. The proposed approach is validated using simulations and compared to the normal implemented TCP where no extension is added to RTO. The simulation results showed higher goodput and less retransmissions compared to standard TCP.