Design And Implementation Of The Node Deployment Algorithm And Adaptive Gateways In Wireless Mesh Network

Wireless mesh network is a typical broadband wireless distributed multi-hop network with self-organization and self-healing. As a new model of network architecture, the wireless mesh network has great advantages over the traditional network in reliability, scalability and flexibility.Faced with an increasingly wide range of wireless network demand, the deployment location of nodes have a direct and significant influence on the topology of the network, network performance and construction costs when the wireless links possess complex and varied features in the planning and deployment stage of the wireless mesh network. However, it lacks a guidance method of choosing WMN node deployment location. Hence, it is desperately needed that the practical and reliable link quality evaluation mechanism and quality display solutions are regarded as the guidances in determining the node location of project deployment. Moreover, when it comes to the device node failures, nodes should take timely adaptive measures to guarantee the network robustness as well as enhance the internet experience.Therefore, the selecting method of the location of nodes in wireless mesh network deployment and issue on the fault-tolerance of gateway devices based on the practical problems encountered among the test deployment are studied in this thesis. First of all, a modified wireless link quality evaluation mechanism based on the LQMP(Link Quality Mesh Protocol) routing protocol is proposed which combines the theoretical research of routing protocol and empirical testing experiences. The mechanism extracts parameters, such as data queue length in the buffer, the average packet delay, the loss rate and the signal strength of neighbor nodes, to provide for the routing protocol which forms supplementary routing metric, and chooses a best next-hop wireless link for data transmission. Thus, it makes a faster and better guidance for WMN deployment project. Then, aiming at repairing issues of the deployment node failure (such as cable disconnections), an adaptive mode switching mechanism through combining with the research of routing protocol is implemented in the thesis. The mechanism can automatically switch the working mode to ServerNode or NormalNode in accordance with the test results. So it ensures the users not to lose the network connection because of the equipment failures.The detailed design and implementation of the improved scheme are completed. The actual field tests are also conducted in the thesis. The test results show that the proposed wireless link quality evaluation mechanism not only can improve the credibility measure of wireless link without significantly increasing the background data stream, but also can provide a more efficient and direct node location selection which guides the test deployment of wireless mesh network. The so-called adaptive working mode switching mechanism is able to complete the automatic model switching when it occurs the design faults, and enhance the robustness of the wireless mesh network.