Abstract:

A modified link layer selective repeat automatic repeat qequest (ARQ) scheme is proposed to improve transport control protocol (TCP) performance over wireless networks——adaptive selective repeat ARQ(ASR-ARQ). According to the feature of every high layer packet being fragmented into several frames at link layer, ASR-ARQ limits the maximum retransmission number per packet and can adaptively allocate retransmission number to frames belonging to the same packet. The link layer packet error rate and transmission delay are derived to evaluate this scheme. The Padhye's TCP throughtput model is also used to evaluate the TCP performance of systems using ASR-ARQ. Numerical results demonstrate ASR-ARQ can achieve much lower packet error rate with slightly longer delay and higher TCP throughput than the conventional scheme.

Key words: transmission control protocol, automatic repeat request, wireless link