TCP Performance Analysis over Aggressive Physical Carrier Sensing Based Wireless Local Area Networks

Aggressive physical carrier sensing (PCS), which improves the spatial reuse efficiency by shrinking the PCS range, is a promising technique to scale high density wireless local area networks (WLANs). Although the aggressive PCS can improve the throughput in MAC layer due to enabling more simultaneous transmissions, it results in serious frame loss rate caused by hidden terminal problems. TCP congestion control is loss sensitive, and thus high frame loss rate degrades TCP throughput seriously. In this paper, we propose an analytical model to investigate the TCP performance with aggressive PCS, and based on the proposed model the TCP throughput is expressed as a function with respect to the PCS threshold. Numerical results show that MAC throughput efficient PCS starves the TCP throughput, and thus we should not adjust the PCS threshold to maximize the MAC capacity in TCP based applications. In addition, extensive experimental results based on StarEast testbed are given to validate the analysis.