Dual Threshold Scheduling for VoIP Traffic on Downlink of WiMAX Networks

Previous downlink scheduling algorithms of WiMAX (Worldwide Interoperability for Microwave Access), like DRR (Deficit Round-Robin) and WRR (Weighted Round-Robin), usually reserve minimum rate to each type of traffic and cannot consider the status of queue length of each connection, thus making it unsuitable for VoIP on-off traffic model. One well-designed scheduling algorithm is expected to coordinate QoS-related functional entities in WiMAX architecture. We address an efficient downlink scheduling algorithm, which allocate the bandwidth based on dual threshold of queue length. We compare the proposed scheme with DRR and WRR by estimating the system performance such as average delay, loss rate and throughput under several traffic scenario and system parameters value.