Media Access Control Protocol Based on Hybrid Antennas in Ad Hoc Networks

Nested Circular Directional MAC, a modified medium access control protocol of DMAC protocol, is proposed in this paper to support both directional antennas and omni-directional antennas simultaneously in one Ad Hoc network. Omni-directional antennas follow the RTS/CTS mechanism which is multi-hop and directional antennas follow the DRTS/DCTS mechanism, ensuring the asymmetric communication effectively. In order to resolve new deafness problem and hidden terminal problem, the directional antennas also use circular DRTS and nested antenna circumrotation. Simulation results show that NCDMAC supports hybrid antennas effectively and is better than MMAC and Circular-MAC in terms of increasing throughput, but it also increases the communication delay.