A Concurrent MAC Protocol based on Local Synchronization for Wireless Ad Hoc Networks with Directional Antennas

Using directional antennas is an effective method to improve the bandwidth utilization in wireless ad hoc networks. However, what remain unaddressed, are the new challenges with MAC protocol design induced by the directional transmissions, such as deafness problems, new hidden terminal problems etc. To solve these problems, in this paper, we propose a directional concurrent MAC protocol based on local synchronization for wireless ad hoc networks with directional antennas. In this protocol, we introduce a channel reservation gap based on local synchronization method for the adjacent nodes, i.e., a channel reservation gap is inserted between the transmission of the RTS/CTS and data packets to offer the neighboring nodes the chance to schedule possible overlapping directional transmissions. Further, the length of the channel reservation gap can dynamically adjust according to the channel situation. Simulation results show that, compared with the typical Nasipuri DMAC protocol, the protocol proposed in this paper can achieve significant throughput improvement.