Enhancing spatial reuse in ad hoc networks by carrier sense adaptation

The optimal choice of the carrier sense threshold for throughput maximization in a Carrier Sense Multiple Access ad hoc network is investigated. We show that the optimal threshold is linearly proportional to a function of the number of nodes and of the network size. When the path loss exponent is 2 (free space) the optimal threshold is linearly proportional to the node density. Given this finding, we develop a modification of the IEEE 802.11 protocol that performs a local and fully distributed adaptation of the threshold that yields about a 40% improvement in throughput, and also outperforms state-of-the-art protocols for CS adaptation.