High Performance Routing Protocols For Wireless Mesh Network

With rapid development of wireless technology, Wireless Mesh Network (WMN) have attracted lots of attention in recent years. WMN are emerging multi-hop wireless networks which inherit the advantages of both WLAN and MANET and provide a cost-effective solution to extend the coverage of existing wireless networks. WMN excels in performance by providing seamless broadband connectivity. Nodes in WMN have the capabilities of scalability, self-healing and self-configuration. These properties provide WMN many advantages such as low upfront cost, easy network maintenance, robustness and reliable service coverage. Due to these properties, WMN are found their applications in various scenarios Routing technology is one of the key technologies of WMN. At present, a large amount of routing protocols in MANET routing have been present, which can also be used in WMN. However, many existing routing protocols in MANET cannot tak full advantage of the characteristics to improve network performance in WMN. Therefore, it is necessary to design special routing protocols for WMN based on these characteristics.On the basis of state-of-the-art researches, high performance routing protocols for WMN are studied through theoretical analysis and simulations. The main contributions of this disseratation are as follows.1. The default routing protocol HWMP for IEEE 802.11s WLAN mesh network based on the draft standard D1.06 from July 2007 is described. Then the workflow of HWMP and its implementation in OPNET are present. Finally, performance evaluation is carried out. The experimental results show that HWMP has lower average latency and higher data transmission throughput compared with the traditional routing protocol for MANET.2. A hierarchical wireless mesh network architecture is proposed based on cluster commonly used in MANET, which divides hybride WMN into three layers. Each layer can also be dived into one or more sub-cluster and the clusterhead of the lower layer is the member of the higher layer. In addition, a cluster-based hybrid routing protocol is presented. Simulation results show that this clustering scheme is more suitable for hybrid wireless mesh network, and the proposed routing has less end-to-end delay, less route discovery time and more throughputs.3. Combined with Dempster-Shafer (D-S) evidence theory, a trust evaluation model is given; meanwhile, a trusted routing is proposed which builts trusted routes according to the node trustworthiness calculated by the proposed trust evaluation model. Simulation results show that the proposed scheme can detect and isolate malicious nodes efficiently, resist attacks to some extent and improve the reliability, robustness and security of the network effectively.4. A novel subjective logic based reputation computation scheme in WMN is present. The scheme incorporates uncertainty based on subjective logic into reputation computation, detects and isolates the selfish mesh routers in the network. It assigns the corresponding weight factor to each opinion from recommenders according to their expectations, which makes the final recommendation results more accurate. This scheme has a reconfirmation procedure for selfish mesh routers, which decreases the false positive rate and improves the network performance. In addition, the scheme considers the quality of wireless links which can differentiate between intentional packet drop and packet drop due to poor link quality and gives accurate detection even in the presence of poor wireless links. Finally, the performance evaluation of the proposed scheme is demonstrated. Simulation results show that the proposed scheme can recognize the selfish mesh routers much more accurately and earlier, and the convergence time for isolating selfish mesh routers is smaller.