An adaptive holdoff exponent approach for coordinated distributed scheduling in WiMAX mesh networks

IEEE 802.16 or WiMAX is the communication technology which has been designed to support high-speed data communication in a wide area for multimedia applications. Thus, there is a need to provide a guaranteed quality of service (QoS) for such multimedia applications while maintaining the overall network performance. This research proposes a scheduling algorithm to improve the network latency in Coordinated Distributed Scheduling approach by adjusting the transmission holdoff exponent to align with the data priority. The holdoff exponent is adaptively adjusted according to node state information to increase transmission opportunity that could reduce average data transfer delay. To demonstrate the performance of the proposed method, we use NCTU-ns simulation with a mesh network topology and multimedia traffic sources such as Voice over IP (VoIP) and real-time video traffic. The results have shown the improvement using the proposed method over a traditional static holdoff exponent method as defined in IEEE 802.16 standard, especially in the network with dense traffic.