A Cooperative Channel Reservation MAC Protocol with Adaptive Power Control and Carrier Sensing

In Vehicular Ad hoc Networks (VANET), wireless channel is a multidimensional resource, involved in time, frequency, space, code and etc. In this paper, a novel channel reservation Medium Access Control (MAC) protocol, called A-CCRM, is proposed to jointly reserve the channel resource in both time domain and space domain. In A-CCRM, the channel reservation time period is computed according to the periodicity of real-time traffics, and the channel reservation space is adjusted by jointly using the techniques of both power control and carrier sensing. Moreover, in order to improve the stability of channel reservation, the annouced channel reservation information is cooperatively relayed by the neighboring nodes of the transmitter. Simulation results show that compared with other MAC protocols based on channel reservation mechanisms, A-CCRM performs better in terms of throughput, energy efficiency and packet lost rate.