A directional MAC protocol with the DATA-frame Fragmentation
and short busy advertisement signal
for mitigating the directional hidden node problem <Abstract> In wireless ad hoc networks, communications using a beam-forming by directional antennas have been discussed because the spatial-reusability efficiency of the wireless channel is improved. The throughput is limited due to the directional hidden node problem in these networks. This paper proposes a Medium Access Control (MAC) protocol for ad hoc networks with directional antennas for mitigating the directional hidden-node problem. In the proposed protocol, the transmitter divides the DATA frame into some DATA fragments and transmits them in succession. The receiver sends the Short Busy Advertisement (SBA) signals periodically and tell the communication situation to the directional hidden node. All the nodes, which detect the SBA signal, defer their transmission opportunities even though they can not receive the Request To Send (RTS) or Clear To Send (CTS) frames. As a result, the frame collisions induced by the directional hidden nodes can be reduced, which enhances the network throughput. Simulation results show the validity and effectiveness of the proposed protocol. |