Traffic Priority Based Adaptive and Responsive Congestion and Rate Control for Wireless Mesh Networks

Congestion Control in Wireless Mesh Networks (WMNs) has been a widely studied context oriented utilization maximization problem. The traffic in WMNs has a wide range of variations (i.e. bandwidth, jitter, delay jitter sensitive applications) due to its use as the backbone network for accessing Internet. Eventually, traffic variation contributes to channel saturation and may bring up congestion due to contention caused by concurrent transmission, buffer overflows and time varying wireless channel condition. In this paper, we propose a distributed congestion control scheme for wireless mesh networks to ensure higher network throughput while avoiding congestion and maintaining inter-flow fairness where real time and non-real time traffic coexists. Our proposed technique handles congestion by restricting the available transmission rate of downstream nodes among the upstream nodes according to their flow demands based on three basic parameters: packet arrival rate, service rate and buffer occupancy. We also introduce prioritized queues in each node to treat real time and non-real time traffic differently. Therefore, congestion degree calculation, rate allocation and prioritizing traffic ensures higher network throughput and guaranteed delivery of real time traffic. Experiments conducted on ns-2 simulations demonstrate that our proposed algorithm can achieve significant improvements in both overall network throughput and inter-flow fairness for both non real time and delay bound traffic.