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Performance Analysis and Boost for a MAC Protocol in Vehicular Networks

This paper proposes an analytical model to investigate the performance of periodical broadcast of safety messages in vehicular ad hoc networks (VANETs), regarding a hybrid medium access control (MAC) protocol, called NC-PNC MAC. We first examine the percent of vehicles involved in subcarrier collisions during a random orthogonal frequency-division multiple access scheme, and then theoretically analyze the total number of transmissions and the packet delivery ratio (PDR) during one dissemination period. Based upon the analysis, this paper not only reveals how the subcarrier collision probability influences the PDR performance, but mathematically obtains the maximum PDR. To confirm the results, by adjusting a pivotal parameter of the MAC protocol, the PDR performance for basic safety message broadcast in VANETs can be enhanced by 10% to 30% under the constraint of the delivery latency.