A Cross-Layer ECN to Achieve Fairness Among TCP Flows in Wireless Mesh Networks

The fair allocation of the resources among different nodes is one of the critical problems in wireless mesh networks. Existing solutions mainly focus on rate-limitation policies or distributed fair MAC schemes at the potential expense of total network utilization. This paper investigates a special starvation problem among TCP flows that are different hops away from the BS, as well as the recently proposed solution, the "Minimum Content Window" policy based on IEEE 802.11e. It is found that the aggregate throughput degrades sharply because the effect of this policy on the TCP congestion mechanism has been overlooked. This paper proposes a priority-based congestion control by using "Cross-Layer Explicit Congestion Notification". Analysis and simulation results demonstrate that our scheme can improve the fairness of TCP flows while the aggregate throughput is at least 20% higher than the "Minimum Content Window" policy.