Achieving near maximum throughput in IEEE 802.11 WLANs with contention tone

Future wireless local area networks (WLANs) promise bit rates higher than 100 Mbps. Previous research by Xiao et al reported that the current IEEE 802.11 medium access control (MAC) protocol does not scale well to high bit rate channels. In this letter, we propose an enhancement that uses contention-tone transmitted on a separate narrow band signaling channel. The proposed contention tone mechanism avoids more than 96% of transmission collisions, hence achieving near to the theoretical maximum throughput of a WLAN MAC protocol.