Study On Centralized Scheduling Mechanism In Mesh Network Based On IEEE802.16d Standard

IEEE802.16 standard has been formally listed as the world's fourth 3G standard by the International Telecommunication Union (ITU). Compared to traditional wireless access technology, IEEE802.16 technology offers a higher speed, larger capacity, and lower cost. IEEE802.16 standard has been paid more and more attention in industry. In all 802.16 standards already promulgated, IEEE802.16d standard defined the air interface physical layer and MAC layer of the 2 ~ 66GHz band in detail, and supported multiply MAC layers and physical layers of multiple service types of broadband wireless access system. So IEEE802.16d standard is the most widely recognized as the most authoritative, the most practical standard. Compared to PMP network, the Mesh network based on this standard has many advantages, such as strong stability, large throughput and so all, therefore, the solution for the key mechanism in Mesh networks based on IEEE802.16d standard become the important research subjects in present.IEEE802.16d Mesh network scheduling mechanism includes centralized and distributed scheduling. In his paper, the study of centralized scheduling mechanism in Mesh Networks based on IEEE802.16d standard is focused on. In the paper the MAC layer protocol of IEEE802.16d standard is introduced, and then compared with other network structure, the characters of Mesh network based on IEEE802.16d standard is analyzed in detail. After this, the scheduling mechanisms of IEEE802.16d Mesh Network are studied.In the study of centralized scheduling mechanism in Mesh Network based on IEEE802.16d standard , a centralized network scheduling research model is constructed, then the methods of generating scheduling tree in centralized scheduling mechanism are discussed in detail, from the perspective of supporting concurrent transmission, an improved method of generating scheduling tree is researched by introducing the concepts such as multi-hop interference and so all, as well as comparing with other methods of generating scheduling tree.Based on the idea of concurrent transmission, a slot allocation algorithm supporting concurrent transmission in centralized scheduling mechanism is designed carefully. Combined with the improved method of generating scheduling tree researched in the paper, the simulations using this algorithm both in uplink and downlink are made. At last, the results of simulations are analyzed, and according to the results of analyze, the performance of this improved method of generating scheduling tree and the slot allocation algorithm supporting concurrent transmission in centralized scheduling mechanism are valued.