ARLP: an adaptive link layer protocol to improve TCP performance over wireless fading channels

Abstract

AbstractImproving the performance of Internet services is essential for future generation wireless networks. However, the correlated fading channels are found to be very unfriendly to transmission control protocol (TCP) performance in such networks. The variation in fading rate brings further challenge to wireless networks when supporting Internet applications, most of which run TCP as the transport layer protocol. In this paper, we first analytically study the performance of different radio link protocol (RLP) retransmission schemes in supporting TCP. In particular, we investigate the key quality of service (QoS) parameters of RLP such as average delay, delay variance and recovery rate of lost frames. Our analytical and simulation results show that a single retransmission scheme does not yield the best performance for different fading rates. To address this problem, we propose an adaptive radio link protocol (ARLP) that dynamically estimates the channel fading rate and also adaptively chooses those retransmission schemes that best fit the estimated fading rate. The performance of ARLP is evaluated in terms of response time (the time ARLP takes to respond to fading rate change), throughput improvement and energy consumption. The results show that ARLP can improve the performance of a particular mobile host as well as the total throughput of wireless networks, at the cost of a little extra energy consumption at low frame error rate. On the other hand, at high frame error rate, ARLP saves energy because of fewer retransmissions. Copyright © 2004 John Wiley & Sons, Ltd.