A Channel Assignment Scheme in High Density WLANs to Mitigate Pesudo Capture Effect

Due to the difficulty of hardware design, the capture effect cannot be realized in the commercial wireless local area networks (WLAN) devices. The status results in a recent emerging pseudo capture effect in high density WLANs (HD WLANs), which is seldom considered before. Existing work has shown that the performance of carrier-sensing multiple access (CSMA) mechanism is severely degraded by this effect in high density WLAN environment. In this paper we present a model to analyze the performance of the effect. Based on the analytical results, a scalable AP-based channel assignment scheme, lowest captured channel (LCC) is proposed, which combats the problem by switching channels of each AP to the channel with the lowest pseudo capture effect. Simulation results illustrate that the proposed scheme increases the system throughput as well as enhances the system fairness compared with the fixed channel assignment. The cost of the scheme is only adding a small overhead for information exchange.