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.