An Adaptive Contention Window Control for Improving DCF Throughput and Fairness

The IEEE 802.11 provides a MAC layer protocol for controlling competition among nodes to access the channel in wireless local area network. Recent works show that this standard has not suitable performances in mobile ad-hoc networks and especially in error prone channels. Many researchers proposed many algorithms to improve this standard like HBCWC (History Based Contention Window Control) scheme has significant performances but also has fairness problem. In this paper, we present a novel contentionbased protocol to improve fairness and throughput together. We use an array to keep history of network collision and based on array information, we optimize the contention window. The main point is that we get higher priorities to nodes had unsuccessful transmissions unlike most of researches. This helps us to solve fairness problem. Simulation results show that compared to the IEEE 802.11 DCF and HBCWC scheme, our algorithm has better performances in term of throughput, fairness, and network overhead load.