An Interference Tolerance Aware Multiple Access Protocol for Wireless Networks

The Distributed Coordination Function (DCF) of IEEE 802.11 is inclined to overestimate the neighboring interferences level when RTS/CTS is enabled, and thus blocks possible concurrent transmissions in a multi-hop wireless network. To improve its spatial reuse we first analyze the spatial reuse efficiency via a spatial utilization parameter taking the interference and transmission ranges into account, and then an Interference Tolerance Aware Multiple Access (ITAMA) protocol is proposed. In ITAMA, a transmitting or receiving node sends its MAC data/control frames with an interference tolerance indicator, which is used to help its neighbors to make more precise assessment of the receiver's tolerance to concurrent interferences. Based on the assessment each neighbor node can make better choices on whether or not to initiate a concurrent transmission. Both analysis and simulation results show that ITAMA can significantly improve the spatial reuse and thus increase the network throughput when the wireless nodes are densely deployed in a network.