Cross-layer QoS support framework and holistic opportunistic scheduling for QoS in single carrier WiMAX system

Providing Quality of Service (QoS) to different service classes with real-time and non-real-time traffic integration is an important issue in WiMAX systems. Opportunistic MAC (OMAC) is a novel view of communication over spatiotemporally varying wireless links. It combines the features of a cross-layer design and an opportunistic scheduling scheme to achieve high utilization while providing QoS to various applications. Channel characteristics, traffic characteristics and queue characteristics are essential factors in the design of opportunistic scheduling algorithms. In this paper, we propose a cross-layer QoS support scheduling framework and a corresponding opportunistic scheduling algorithm to provide QoS support to the heterogeneous traffic in single carrier WiMAX point-to-multipoint (PMP) systems. We model the uplink transmission in the single carrier WiMAX system as a multi-class priority TDMA queueing system to analyze the average packet delays of different service classes. Extensive simulation experiments have been carried out to evaluate the performance of our proposal. The simulation results show that our proposed solution can improve the performance of the WiMAX PMP system in terms of packet loss rate, packet delay and system throughput.