Analyzing and improving the TCP flow fairness in 802.11 based ad hoc networks

The TCP flow fairness problem in 802.11 based multihop ad hoc networks was studied in this paper. Firstly, a probability model was established to describe the TCP flow fairness, and its rationality was verified by simulation; Then, a new MAC layer scheme with low overhead cost was proposed, in which the backoff window at MAC layer was controlled by detecting the basic factors that lead to the TCP flow unfairness, and so the TCP flow fairness was improved. The proposed algorithm was simply and easy to implement, simulation results show that it can eliminate the TCP flow monopoly phenomenon, improve the TCP flow fairness validly and without significantly impairing aggregate throughput in multihop ad hoc networks.