Research On Internet Gateway Placement In The Backbone Of Wireless Mesh Networks

Wireless broadband access was requested for even higher requirements recently with the development of the wireless communications and mobile computing techniques. Wireless network is one of the key techniques used by the future wireless communications to replace the wired network gradually, which implements the high-capacity and high-speed Internet access. However, there were some problems in the existing wireless network, such as narrow coverage, poor communication reliability. As a novel wireless broadband access technique with great advantages and potentialities, Wireless mesh networks (WMN) can solve problems above effectively, and it is bound to become one of core techniques of the future wireless communications.The thesis summarizes the advantages of the wireless mesh network compared with the traditional wireless access techniques, meanwhile analyzes its features, limitations and the critical techniques related. Then it emphasizes on the Internet gateway placement and discovery which are two critical techniques and analyzes the deficiencies and technical challenges of current solutions to the gateway placement and discovery in detail.Firstly, an algorithm is presented based on the existing problems of the gateway placement in the backbone of WMN. According to specific conditions of network, this algorithm can implement the minimal number of the placed gateway and the minimal hops between the routers and gateways. And then the simulation analysis of performance of the algorithm is made under different network states. The results show that the algorithm is able to reduces the delay of the network communications, and at the same time makes the throughput of each gateway in the network meet the requirements of the network traffic.Then, an adaptive dynamic multi-metric gateway advertisement algorithm is also presented based on the existing problems of gateway discovery in the backbone of WMN, which makes dynamic adjustments according to the state of the whole network, selects gateways routing considering congestion and comptitve caused by nodes. And then experiment is done for verifying the performance. The experimental results show that the algorithm reduces the network overheads in gateway discovery effectively, meanwhile avoids packet loss caused by excessive traffic in certain area and thus improves the packet delivery rates.