IEEE 802.16無線都會網路下以優先權為主之可適性排程機制

Abstract

Supporting QoS guarantees for diverse multimedia services is the main concern in IEEE 802.16 networks. The scheduling scheme to satisfy QoS requirements become more important issues in IEEE 802.16 networks. Therefore we propose a scheduling scheme in the thesis, called Adaptive Priority-based Scheduling (APS) scheme for provision of QoS guarantee in IEEE 802.16 networks. APS comprises two major components, including priority assignment and resource allocation. Basically, five service types in APS are reasonably classified into the Delay-Constrained Service (UGS, ertPS, and rtPS) and the Throughput-Guaranteed Service (nrtPS and BE) categories, primarily depending on their QoS requirements. In priority assignment, each connection in the individual category is assigned a suitable priority by using a well-designed rule, based on the connection’s QoS parameters. Additionally, in order for starvation prevention, the priority of the connection with low priority in each category will be dynamically promoted. In resource allocation, the maximal and the minimal bandwidth requirements are first calculated. After comparing such bandwidth requirements and the total available bandwidth of BS, we consider the priority of a connection, and then make use of the weight-based proportional fairness scheme to achieve resource allocation of each connection. Overall, APS is not only completely compatible with DFPQ scheme and SCSA scheme, but also achieve QoS satisfaction as well as starvation prevention. Simulation results show that APS outperforms the representative scheduling approaches in both average throughput and average delay.