Range sensitive multiple access protocol for wireless local area network with smart antennas

Using smart antennas to extend the coverage range and capacity of wireless local area network (WLAN) requires new multiple access protocols, by which the access point (AP) can connect remote stations residing beyond its broadcast coverage area. In this paper, we propose a novel and efficient medium access control (MAC) protocol for WLAN with smart antennas, called Range Sensitive Multiple Access Protocol (RSMA). Using the hybrid superframe structure of contention-free periods and contention periods, the proposed RSMA distinguishes stations residing within broadcast coverage range of the AP from those out of range. For stations residing within the AP’s broadcast range, the AP uses polling to transmit in broadcasting mode; for those residing outside the AP’s broadcast range but in its directional range, the AP uses a contention-based method to transmit in beamforming mode. By simulation, we evaluate average packet delay and network throughput to find the optimal values of protocol parameters. Moreover, to show the efficiency of RSMA, we also compare its performance with that of three other protocols. The simulation results show that RSMA is more efficient and robust than the others, and more importantly, it can extend the coverage range of WLAN to support data exchange between the AP and stations residing out of its broadcast range.