An analytical model for the hybrid PQ-WFQ scheduling scheme for WiMAX networks

The provisioning of differentiated QoS is an important objective in the design and implementation of IEEE 802.16 / WiMAX-based broadband wireless networks. To this end, the hybrid scheduling mechanism that combines various fundamental scheduling principles, e.g., priority queueing (PQ), earliest deadline first (EDF), weight fair queue (WFQ), and round robin(RR) within a hierarchical structure for bandwidth and buffer sharing has been proposed to support the differential QoS requirements in WiMAX networks. This paper proposes analytical models for the hybrid scheduling scheme that integrates PQ and WFQ in the presence of non-bursty Poisson arrival process and bursty Markov modulate poisson process (MMPP), respectively. We derive the expressions for the performance metrics including the mean number of packets in the queue, throughput, mean queueing delay and packet loss probability, and fairness of individual traffic flows. The model is adopted to investigate the effects of the weight of the WFQ policy and traffic burstiness on the performance of the hybrid scheduling system.