Mobility-based backoff algorithm with optimal window for vehicular network access

As a part of vehicular network, V2I communication plays an important role in many aspects such as internet access, traffic information acquisition, ETC and so on. IEEE 802.11p is one of the most widely used access protocol, which adopts binary exponential backoff algorithm (BEB). However, in vehicular environment, BEB algorithm can't make any adjustment with the change of real-time network status and high mobility of vehicles. It causes serious unfairness problems and a large amount of collisions under the condition of high-traffic vehicular network. This paper proposes an algorithm called MBAOW (Mobility-based Backoff Algorithm with Optimal Window), which uses a constant optimal contention window in backoff stage. The window can be adjusted with the the vehicle speed and the network status. The simulation results validated the effectiveness of MBAOW as well as the accuracy of the proposed model. The access performance including the fairness, reliability, throughput can be improved.