Comparison of WiMAX scheduling algorithms and proposals for the rtPS QoS class

Scheduling algorithms are of utmost importance in WiMAX for efficient use of radio resources. A scheduling algorithm should take into account the WiMAX QoS classes and service requirements. It should also provide high throughput. In this paper, we propose a review of scheduling algorithms proposed for WiMAX. We focus on the real-time Polling Service (rtPS) QoS class. NS-2 simulations show interesting results. We highlight a problem that may exist with the WiMAX rtPS QoS class and we provide solutions for it. Simulation results concerning proposed WiMAX schedulers are discussed. We propose an enhancement of the maximum Signal-to-Interference Ratio (mSIR) scheduler, called modified maximum Signal-to-Interference Ratio (mmSIR). We show through extensive simulations that this enhancement provides better mean sojourn time in addition to an improvement in throughput.