RI-DMAC: a receiver-initiated directional MAC protocol for deafness problem
Although the use of directional antennas in ad hoc networks is expected to provide significant improvements, directional MAC protocols inherently introduce new kinds of problems. Deafness is one of the major problems caused when a transmitter repeatedly attempts to communicate with its intended receiver, but it fails because the receiver has its beam pointed away from the transmitter. This paper proposes Receiver-Initiated Directional MAC (RI-DMAC) to handle the deafness problem. RI-DMAC is a combination of sender- and receiver-initiated operations. The sender-initiated mode is the default mode and the receiver-initiated mode is triggered when the transmitter experiences deafness. Each node maintains a polling table and polls a deafness node using the Ready to Receive (RTR) frame after the completion of every dialogue. Simulation results show that RI-DMAC outperforms other directional MAC protocols (e.g. Basic DMAC and Circular RTS MAC) in terms of throughput, fairness, overhead and packet drop ratio.
directional mac protocol deafness directional antennas ad hoc networks smart antennas medium access control dmac protocol receiver-initiated mac protocol ieee 802.11