A distributed scheduling algorithm for mobile WiMAX networks

In this paper, we propose a scheduling algorithm for mobile WiMAX networks that distributes dynamically the bandwidth among service flows while giving real-time packets more chances to satisfy their QoS requirements. The scheduling in the proposed algorithm is assisted by the subscriber stations, hence requiring two-schedulers, a scheduler at the BS and another one at the SS, where preemption is applied to both of them. At the SS, a preemptive queue being serviced can be preempted if a packet which cannot be delivered within its deadline arrives to a non-preemptive queue. However, at the BS, preemption is only feasible if a critical packet arrives to a non-preemptive downlink queue. The proposed algorithm was integrated with the network simulator NS2 using the MAC layer of the NDSL WiMAX module, then compared its performance to other peer algorithms found in the literature. Simulation results have shown that the proposed approach enhances the throughput and the average delay of real-time QoS classes.