SUMA - the synchronous unscheduled multiple access protocol for mobile ad hoc networks

The use of unscheduled contention based channel access protocols in mobile ad hoc networks is very attractive due to their transparency to topological change, relatively low overhead, and ease of implementation. Recent reports (see Shugong Xu and Tarek Saadawi, IEEE Commun. Magazine, vol.39, no.6, p.130-7, 2001), however, have shown that the widely available asynchronous contention based 802.11 protocol has significant fairness issues, especially with regard to exposed terminals. These fairness issues are a direct result of the asynchronous nature of the protocol. We present SUMA, the synchronous unscheduled multiple access protocol, which has all the benefits of a contention based access protocol while ensuring fair access to all nodes.