Distributed Physical Carrier Sensing Adaptation Scheme in Cooperative MAP WLAN

Recently a multiple access point (MAP) architecture is proposed for wireless local area networks (WLAN) to exploit the spatial diversity by permitting each user to associate with multiple APs. Benefited from multiple association, the promising cooperative communication technology can be utilized to further enhance the spatial diversity gain. However, cooperative transmission results in low spatial reuse efficiency with traditional physical carrier sensing (PCS) mechanism. That is because multiple cooperative nodes transmit simultaneously, which causes interference to the adjacent nodes and prevents their transmissions. Therefore the PCS range should be decreased aggressively to support more parallel cooperative transmissions. In this paper, a distributed PCS tuning scheme is proposed to enhance the spatial reuse efficiency in cooperative MAP WLAN. A cooperative node selection scheme is jointly designed to avoid the excessive interference caused by cooperative nodes transmission. Simulation results show that the proposed scheme significantly improves the throughput of cooperative MAP WLAN.