A Heuristic Strategy for IEEE 802 . 16 WiMAX scheduler for Quality of Service

The advent of Broadband wireless promises quality communications over the wireless channel. The 802.16 standard is expected to arise as the main Broadband Wireless Access (BWA) Technology, providing high-speed data access to subscribers. In this paper, an important part of such a network, the MAC scheduler, is investigated. Although IEEE 802.16 defines specific Quality of Service (QoS) traffic flows, scheduling of heterogeneous applications is left open for research. A heuristic approach is followed to propose a QoS strategy. In the proposed strategy, Call Admission Control (CAC) is implemented for high-priority traffic so as to overcome the problem of starvation of network resources. Moreover different contention minislots allocation strategies, for low-priority traffic, are investigated. The performance of these strategies is simulated via Opnet modeler for several scenarios. Medium Access Control (MAC) delay and throughput rate are used as measures to gauge the efficiency of the protocol for every specific class of service. The quality demands of each class are analyzed and used as input for the heuristic strategy. The results show that effective scheduling can provide high service standards, competitive to other modern cellular networks. The target of the paper is to demonstrate the possibilities for market applications of WiMAX (Worldwide Interoperability for Microwave Access) taking into account the quality of service features and the capability of vendor oriented MAC scheduling.