A Markov Chain Based Model for Congestion Control in VANETs

Vehicular networking has significant potential to enable diverse applications associated with traffic safety, traffic efficiency and infotainment. In this paper, we address the issue of congestion in Vehicular Ad Hoc Networks (VANETs). In VANETs, the periodic beacon broadcast may consume a large part of the available bandwidth, which may lead to severely affect the dissemination of the event-driven warning messages. To address this issue, we propose a novel Markov chain model that consists of four steps: priority assignment, buffer monitoring, congestion detection phase, and beacon transmission rate adjustment to facilitate emergency packets propagation. Our model brings many improvements to IEEE 802.11p as it allows anticipating congestion. The simulation tests show promising results and validate our solution.