NOMAD: Deterministic collision-free channel access with channel reuse in wireless networks

The Neighborhood Ordering for Medium Access with Determinism (NOMAD) protocol is introduced. NOMAD defines collision-free transmission schedules dynamically and with no need for a predefined number of time slots per transmission frame by coordinating circular permutations of the identifier of nodes in the neighborhoods shared among nodes. NOMAD is shown to attain feasible transmission schedules within a short finite time and to provide channel access intervals of negligible variance. The performance of the NOMAD is compared with the performance of 802.11 DCF and the node activation multiple access (NAMA) protocol, which is representative of distributed transmission scheduling based on probabilistic elections. NOMAD is shown to attain higher throughput than 802.11 and NAMA in static and dynamic ad hoc networks, and to eliminate the large variances in channel access times present in contention-based schemes and prior transmission-scheduling schemes that do not use reservations.