A hybrid MAC scheme for wireless vehicular communication

One key goal of Vehicular Ad-hoc Networks (VANETs) is to provide sufficient Quality-of-Service (QoS) for real-time safety applications. These applications facilitate wireless broadcast warning messages between neighboring vehicles to inform drivers on time about dangerous situations like accidents. The IEEE 1609.4 standard in DSRC defines a MAC layer implementation for multichannel operations in VANETs for such broadcasts. In this paper, we present a distributed hybrid MAC scheme for emergency systems. The proposed scheme improves the Control Channel (CCH) utilization and uniformly distributes the load on Service Channels (SCHs). In the proposed scheme, the network switches its mode from general to emergency in order to effectively utilize common service channels thus increase the probability for timely reception of messages. In addition, the proposed scheme reduces the rate of transmission collisions and latency, thus resulting in high probability of message delivery. The propose MAC scheme is simulated and compared with the existing MAC schemes. The obtained results depict that the proposed hybrid scheme outperforms its competitors and thus validates its performance.