An Efficient Broadcast Scheme for Safety-Related Services in Distributed TDMA-Based VANETs

The medium access control (MAC) protocol should provide an efficient broadcast service to support the high-priority safety applications in vehicular ad hoc networks (VANETs). Basic safety messages (BSMs) transmitted through vehicle-to-vehicle and vehicle-to-infrastructure architectures are the most fundamental of these applications. The periodic transmission of BSMs results in a heavy burden on the load of the VANETs when traffic density is high, and the presence of hidden terminals degrade the performance of the network. This letter introduces a distributed time division multiple access (TDMA)-based scheme that controls the transmission range to improve the efficiency of BSM transmissions in VANETs. The transmission collisions can be reduced without lowering the awareness quality of the surrounding nodes at a close range. Meanwhile, merging collisions can be pre-detected and eliminated by cooperation among the nodes. Simulation results demonstrate that our strategies can provide an efficient and reliable BSM broadcast service.