A TDMA-based channel access scheme for achieving fairness in inter-vehicle communications

Wireless access in vehicular environment brings new challenges. One of the most common issues is about designing a channel access scheme for Vehicle-to-Vehicle (V2V) communications, which is affected by several number of factors such as high density of vehicles, direction of traveling, location and speed of vehicles, instability of communication links, and absence of fixed infrastructures. The IEEE 802.11p/1609.4 WAVE protocols aim to cope with these issues through adopting a contention-based approach. However, various simulation experiments vote the weakness of the IEEE 802.11p/1609.4 protocols to provide scalability, reliability, predictable delay and fairness. Meanwhile, contention-free methods have been offered by researchers to address these requirements. However, there are only a few number of contention-free schemes for VANETs in the literature, which consider fairness. In this paper, a Time Division Multiple Access (TDMA) based multichannel assignment scheme is proposed to address the fairness issue in sharing wireless medium. The proposed method is an extension of TC-MAC and apart from improving fairness; it tries to preserve the bandwidth utilization via an enhanced slot reservation mechanism.