A distributed TDMA-based MAC protocol for Ad Hoc networks with directional antennas

To improve the network capacity and reduce interference, directional antenna has been used in ad hoc networks for a long time. Due to the drawbacks of random access MAC protocols with directional antennas such as inevitable collisions, a distributed TDMA-based directional MAC protocol for ad hoc networks is proposed in this paper. It takes the advantage of real-time capability of TDMA and spatial reuse potential owing to directivity. By using the binary countdown mechanism instead of CSMA/CA, collision is completely avoided in contention stages. It offers priority services as well. The network saturation throughput and average delay are analyzed theoretically. Simulation results show that this new protocol performs better than DMAC protocol, as well as IEEE802.11 DCF and TDMA-based protocol with omnidirectional antennas.