MCDA: an efficient multi-channel MAC protocol for 802.11 wireless LAN with directional antenna

IEEE 802.11 provides a contention based MAC protocol for single channel wireless environment. Extending IEEE 802.11 to a multi-channel environment will not only exploit the bandwidth utilization but also reduce the degree of contentions. Involving directional antenna in designing multichannel MAC protocol additionally increases the spatial reuse, allowing more communications proceeding in parallel. This paper proposes an efficient 802.11 multi-channel MAC protocol with directional antenna (MCDA). Since each station is only equipped with a single antenna, communicating pairs that progress their communications on data channels will unable to maintain the channel usage information which is only obtained from the control channel, raising the channel collision problem. The proposed protocol adopts mechanism of channel switch sequence (CSS) to resolve the channel collision problem and reduce the overhead in message exchange for switching channel. According to the state management, MCDA then controls directional antenna transmitting data on a selected channel to exploit the opportunities of spatial reuse and maintain the fairness among communicating pairs. Simulation results show that the proposed MCDA protocol can largely improve the bandwidth utilization and throughput while the fairness could be maintained.