A Novel Hybrid Uplink Bandwidth Scheduler in WiMAX Real Time Communication Networks

As Scheduling for real time polling services (rtPS) is not defined in IEEE 802.16 standard, there are various approaches described to address this issue. IEEE 802.16 has detailed documents about the QoS parameter. However, they do not mention the scheduling algorithm to be used. The essential goals of this packet scheduling scheme are to guarantee the QoS parameter as well as provide fairness among the subscriber stations. In this paper, we first use Earliest Deadline First (EDF) algorithm to schedule the real time service according to the QoS requirement. This meets maximum delay and packet loss requirements of a subscriber station in WiMax communication networks. In addition to satisfying the QoS requirements, we modify and extend the Proportional Fairness scheduling algorithm to what we call the Subscriber Stations Based Proportional Fairness (SSBPF) algorithm, which allocates remaining bandwidth fairly amongst subscriber stations. The algorithm has been implemented and evaluated in a WiMAX simulation platform developed in OPNET. From the simulation results, we can see not only the QoS requirement is satisfied, but also is fair to all subscriber stations in WiMax networks.