Research On Hierarchical Routing Protocol For Wireless Mesh Networks

This dissertation is about the study and improvement of routing algorithm in Wireless Mesh Network. The Wireless Mesh Network (WMN) is a multi-hop broad bandwidth distributing wireless network with high capacity and high transmission rate. WMN is capable of self-organization and self-configuration. WMN is in substance a kind of Ad Hoc with low mobility. As a new type of network structure, Mesh is included into 802.16-2004, 802.16e and 802.11s standards.It is first introduced that what the Wireless Mesh Network is and the architecture of WMN. Then it gives a snapshot of some former typical wireless self-organizing network routing protocols. The principal and performance of these protocols are analyzed and compared using Network simulator. On basis of these researches, this dissertation proposed two layered routing algorithms for the two major network architectures of WMN, which are Infrastructure/Backbon WMN and Client WMN, respectively. Also the simulations are worked out to verify the algorithms.For Infrastructure/Backbon WMNs, this dissertation proposes a hybrid routing algorithm with layered network architecture (HRLN). In the layered WMNs, mesh routers form an infrastructure of WMNs and provide wireless network access for mesh clients. With gateway functionality, mesh routers can be connected to the Internet. With mesh routers, mesh clients can communicate with any note inside or outside WMNs. The hybrid routing algorithm combines the advantages of both table-driven and on-demand routing algorithms. Simulation results show the higher delivery fraction and lower overhead of the proposed HRLN compared with AODV and DSDV.A typical application of Client WMNs is wireless sensor network, which consists of a large number of small sensors with limited battery power, gathering data and perform coordinated tasks in various environments. How to prolong the network lifetime with the limited power of sensors is a key challenge in designing a wireless sensor network. It may save energy to cluster sensors into groups, so that sensors communicate only to cluster-heads and then the cluster-heads communicate the aggregated information to the base station. Based on LEACH protocol, this dissertation proposes an optimal algorithm for the non-cluster head nodes to choose the best cluster-head, which takes the current energy of the cluster-head into consideration. By balancing energy depletion over the whole network, simulation results show that the proposed algorithm outperforms LEACH protocol and prolongs the network lifetime.