The Research On Cross Layer Approach Of MGMP For Wireless Mesh Networks

Wireless Mesh Networks(WMN) is a new wireless broadband access network, which combines the advantages of wireless LAN and mobile ad hoc networks (Ad Hoc), and is a large capacity, high-speed, wide coverage network, which becomes an effective means of broadband access. It is a key issue in the design of Wireless Mesh Networks to find a route protocol with high quality and efficiency communications between the two nodes, and it is an important guarantee to research and design appropriate route, which will give full play to the advantages and performance of Wireless Mesh Networks.the paper analyzed the three existing typical route protocol of Wireless Mesh Networks: ExOR, HWMP and MGMP, then tested them by NS-2 simulation platform. The conclusion of the test results is that MGMP has significant scalability advantages based on balancing network load, improving network reliability and fault tolerance, so this thesis takes MGMP as the research object, and propose three kinds of cross-layer optimization mechanisms:1) route measure selection and link filter mechanism: Link filter mechanism optimizes the network topology by filtering of some low-speed, high error rate links according to the changes in the physical layer channel. Using the combination of link's ETX and minimum hop can synthetically consider the link quality and network path hops to select the better route.2) back pressure scheduler: Each radio dynamic manages some packets-send queues and schedul them based on back pressure of the queue. This mechanism not only can better play the multi-path advantages of MGMP, but also can ensure the fairness of the flows.3) routing cache mechanism supporting dynamic channel adjustment: When the radio is scanning the channel or switching the channel, routing cache mechanism supporting dynamic channel adjustment can cache the packets, so it can reduce the packet loss and end to end retransmission.Finally, we build a small Mesh prototype network for performance testing, test results show that cross-layer optimization of MGMP routing protocol can improve network throughput significantly.