A Novel Multichannel Multiple Access Protocol for Vehicular Ad Hoc Networks

A novel multichannel multiple access (MMA) protocol is proposed for vehicular ad hoc networks in this paper. For increasing channel efficiency, two control channels are utilized in MMA to finish request-to-send/clear-to-send (RTS/CTS) interactions and acknowledgments (ACKs) separately. When a collision happens in the control channel, the waiting period before the next re-transmission is adjusted by a relative mobility based back-off scheme. Benefiting from the fully distributed channel selection scheme, which is also included in MMA, the data transmissions carried in the chosen service channels can be successfully accomplished without collision, and the influence of exposed terminals can also be effectively alleviated. Simulation results show that MMA outperforms the classic single channel and multichannel MAC protocols in average channel utilization, packet delay, and packet drop rate.