A queue based dynamic approach for the Coordinated distributed scheduler of the IEEE 802.16

The IEEE 802.16 standard is currently one of the most interesting broadband wireless access. One key issue of mesh networks is the MAC (Medium Access Control) layer. The scheduling and assignment of transmission opportunities can be realized in centralized or distributed manner. In this paper we analyze the IEEE 802.16 election based mechanism for the Coordinated Distributed Scheduling (CDS). In order to analyze performance of this scheduling mechanism we implemented a new MAC module for the IEEE 802.16 mesh mode in a well-known simulation tool, ns2. Moreover, we developed a queue size based approach to dynamically set a typical parameter of the CDS, called XmtHoldoffExponent (XHE). This dynamic adaptation mechanism is able to enhance the performance of the network in terms of throughput and average end-to-end data packet delay despite of the increased average setup latency, that is the average interval time of acquiring a new transmission opportunity..