Study On Scheduling Mechanism In Wireless Mesh Network Based On IEEE 802.16 Standard

As the development trend of the next generation broadband wireless communication technologies, broadband wireless Metropolitan Area Network(IEEE 802.16 standard) offers higher speed, larger coverage, and lower cost than traditional wireless access technologies. Wireless Mesh Network(WMN) is a kind of multipoint-to-multipoint wireless multihop networks with great capacity and high speed. In WMN, every node is capable of routing and only communicates with its neighbors. WMN has many advantages, such as strong stability, large throughput and easy expanding over traditional point-to-multipoin(PMP). Collision avoidance mechanism, routing constructing and scheduling mechanism in IEEE 802.16 Mesh Mode become the important research subjects.The problem solved by scheduling mechanism mainly is bandwidth resource allocation in wireless networks. In the basis of analyzing IEEE 802.16 Wireless Mesh Network, the thesis mainly studies two different scheduling mechanism of IEEE 802.16 Mesh Mode including centralized scheduling and distributed scheduling. At last, the thesis proposes the new resource scheduling programs based on different scheduling mechanism.According to centralized scheduling, we first analyze a variety of routing constructing algorithms, and then, propose a united routing algorithm based on mini-hops and mini-collision. In terms of resource scheduling algorithm, we adopt an advanced concurrent transmission scheduling algorithm based on collision avoidance. The new centralized resource scheduling program is composed of two algorithms above. Finally, we set up simulation platform in order to assess the performance of the program. The research results show that, the network throughput is improved using our program.According to distributed scheduling, we first introduce the scheduling process of minislots in the date sub-frame, and then, propose an adaptive slot allocation algorithm based on QoS guarantee through improving a simple data channel slot allocation algorithm. The simulation results show that, taking into account both the request failure rate and the slot utilization rate, the algorithm not only provides QoS guarantee for real-time business but also reduces the average packet delay, thereby increasing network throughput.