Performance enhancement of wireless LANs through packet combining

Wireless local area networks (WLANs) are faced with the presence of hidden terminals and the possibility of capture when operating in multipath radio channels. These phenomena complicate both their design and performance analysis. We consider a WLAN with CSMA/CA MAC protocol over mobile radio channels and evaluate its performance in terms of average throughput and average packet delay. In order to improve the system performance, we propose the use of different packet combining methods where the receiver keeps wrongly detected packets, combines them with their retransmitted versions and then makes a decision. Such a simple technique is well suited for wireless LANs since it provides a diversity gain to the system that can reduce interference problem (hidden terminal situation) and improve the capture effect. Simulation results show that both maximum ratio packet combining (MRPC) and hard decision can achieve a considerable gain in system throughput.