Abstract: | IEEE 802.11p protocol is the MAC layer and physical layer standard designed for wireless access in vehicular environment. The backoff algorithm it utilized is Binary Exponential Backoff(BEB). BEB doesn’t adjust along with the change of the vehicle speed and the network status, which will lead to serious unfairness and collision in vehicle-to-
infrastructure communications. So it can’t be well applied to the vehicular network. In order to solve these problems, a novel algorithm is proposed, which uses a constant optimal contention window in backoff process. The contention window can also be adjusted with the vehicle speed as well as the network status got from roadside units. The mathematical analysis and simulation experimental results show that the proposed algorithm in this paper can obviously improve the performance of channel access such as throughput, fairness, reliability and so on. |