WTCP: an efficient mechanism for improving TCP performance over wireless links

The transmission control protocol (TCP) used in the Internet has been mainly designed assuming a relatively reliable wireline network. The TCP assumes that any loss is due to congestion and consequently invokes congestion control measures. This has been shown to yield poor performance in the presence of wireless links as a large number of segment losses will occur more often because of wireless channel errors or host mobility. We present an efficient transmission control scheme (WTCP) that requires the base station to buffer data packets destined for the mobile host and retransmit lost packets. Through simulations, we show that our scheme yields better throughput than other existing proposals while maintaining the TCP's end-to-end semantics. One salient feature of WTCP is that it effectively hides the time spent by the base station to locally recover so that the TCP's round trip time estimation at the source is not affected. This is critical since otherwise the ability of the source to effectively detect congestion in the wireline network will be hindered.