Abstract

Abstract—In this paper, the performance of carrier-sense multi-ple access (CSMA)/collision-avoidance (CA) protocols in the presence of carrier-sensing errors is analyzed. Two types of carrier-sensing errors, i.e., false alarm and miss-detection, are con-sidered, and their impact on the system performance is analyzed using a new CSMA/CA model based on a Markov chain capturing the sensing error at the physical layer. The system throughput and delay as functions of the sensing error probabilities, as well as other CSMA/CA parameters, are obtained, and their sensitivity with respect to a key physical-layer parameter, i.e., the sensing threshold, is analyzed for commonly used energy detectors or matched filters. It is shown that the throughput and delay sensi-tivity heavily depends on the ratio of the contention window size W to the frame length L, and the throughput is sensitive to the design of the sensing threshold when the ratio W/L is either small or large. The result provides guidelines about how to operate CSMA/CA considering imperfect sensing at the physical layer. Index Terms—Carrier-sense multiple access (CSMA)/collision avoidance (CA), carrier-sensing errors, delay, energy detector, matched filter, performance analysis, sensitivity, throughput, wireless local area networks (WLANs). I.