BTAC: A busy tone based cooperative MAC protocol for wireless local area networks

Spatial diversity is an effective technique to mitigate the negative effects of fading and depends on deployment of antenna array on small mobile unit. This is infeasible due to the small size of the mobile node. In order to overcome this limitation, a new concept of diversity that has emerged called cooperative diversity is realized. In this technique, different nodes in a wireless network are allowed to share their resources and cooperate through distributed transmission, forming multiple transmission paths to the destination. In this paper, we introduce a cooperative MAC-protocol, called BTAC, for improving throughput in multi-rate wireless LANs. BTAC is compatible with IEEE wireless LANs. Our analytical and simulation results show that the proposed protocol can improve the throughput performance by at least 35% and substantially reduce system delay, comparing IEEE 802.11b MAC protocol. In addition this protocol is robust and fair.