A Fully Distributed TDMA based MAC Protocol for Vehicular Ad Hoc Networks

—The Vehicular Ad-Hoc NETwork (VANET) consists of a set of vehicles moving on roads which can communicate with each other through ad hoc wireless devices. VANET has attracted a lot of attention in the research community in recent years with the main focus on its safety applications. One of the challenges for vehicular network is the design of an efficient Medium Access Control (MAC) protocol due to the hidden node problem, the high speed of the nodes, the frequent changes in topology, the lack of an infrastructure, and various QoS requirements. Motivated by this observation, we design a fully distributed and location-based TDMA scheduling scheme for VANETs networks, named DTMAC. The main goal of this work is to propose a MAC protocol that can provide fairness in accessing the transmission medium, as well as reduce access collision and merging collision under various conditions of vehicular density without having to use expensive spectrum and complex mechanisms such as CDMA or OFDMA. An analytical model of the average access collision probability and throughput are derived which can be used to evaluate the performance of DTMAC protocol as well as to validate the simulation results under different traffic conditions