A CSMA/TDMA dynamic splitting scheme for MAC protocol in VANETs

The MAC protocol can minimize simultaneous channel access attempts in an effort to decrease the interference and thereby increases reliability, which is vitally important for VANETs (vehicle ad hoc networks). In this paper, an adaptive hybrid MAC (Medium Access Control) scheme is proposed for VANETs, in which the transmission frame is split dynamically into two parts according to the traffic load. In the first part, CSMA/CA (Carrier Sense Multiple Access method with Collision Avoidance) is adopted as the access technology, and in the second one, STDMA (Self-organizing Time Division Multiple Access) is exploited. We implement simulations with various traffic loads in the MATLAB platform, and the simulation results show that the proposed scheme is reliable and can achieve better performance in channel access delay and packet drop probability than both pure CSMA/CA and STDMA schemes.