Improved Fair Scheduling Mechanism in Distributed WiMAX Mesh Networks

In Distributed WiMAX Mesh Networks (DWMN), a joint solution with FEBA (Fair End-to-end Bandwidth Allocation) and DRR (Deficit Round Robin) can be used to achieve high end-to-end throughput fairness. Even then, the higher the number of hops a traffic flow traverses, the longer becomes the end-to-end delay of the traffic flow. This will result in serious unfairness of service quality among real-time traffic flows with different path length since they are delay-sensitive. In this paper, an improved fair scheduling mechanism based on the previous joint solution is proposed to deal with the above-mentioned problem by assigning a greater scheduling weight to the relayed traffic flows. Moreover, a new fairness index is defined to evaluate the service quality fairness of traffic flows. The proposed mechanism is compared with the previous joint solution by simulation. The results indicate that our proposed mechanism can provide better service quality fairness among real-time traffic flows without decreasing their throughput fairness. And it is also effective to improve the service quality fairness and throughput fairness of non-real-time traffic flows when the network is under a certain load.