The Research On Multicast Routing And Channel Assignment Algorithmin Wireless Mesh Network

WMN(wireless mesh network) is a new kind of technology in the wirelessnetwork, this network can provide network audio, video meeting, Internet chat roomand other services for user. WMN is self-organizing networks and usually composeswith static mesh routers, nodes constitute network and maintains its connectionautomatically in order to acquire greater coverage and better reliability, so it canreduce the equipment cost. In the wireless mesh network there have unicast,multicast, and broadcast transmission. along with the rising number of users, theuser’s requirements are constantly improving, single unicast transmission mode hasbeen unable to afford the requirements of users, so a lot of research begin to payattention to multicast in the network performance research.In the multicast network, the source node needs to sent the message to multiplereceivers, this requires greater network capacity. The network capacity is limited,however, in order to improve the network capacity further, multi-channel andmulti-interface have been introduced to the network, the design of efficient multicaststrategy has become the point of current research, mainly concentrated in two aspects:one is the reasonable and effective routing algorithm, which is generally solved byconstructing a multicast tree; the other is multi-channel allocation problem, how toassign the channel for radios and to minimise the interference. To solve theseproblems, this paper introduces the typical multicast routing policy and many keyissues of multi-channel multi-interface, mainly made the following works.(1) In the view of Wireless Mesh Network multicast routing problem, the paperproposed a multicast tree construction algorithm joint link quality and the load. Thescheme make link quality and link load as a selection criterion when chose themulticast path in multicast tree constructing. First, built a initial multicast treeconsidering the minimum path. Then according to the build multicast routing criterion,constructed a multipath multicast tree, which will choose the path that has higherreliability when choosing the path. At last, the reliable multicast tree is contructed bythe combination of two trees, not only meet the requirements of reliability, also canmeet the requirements of resources using. And when a node or link is failure, it can be repaired by alternate path, avoiding the re-establish of routing. Simulation resultsshow that this scheme can improve the success rate of packet transmission, reduce theaverage delay, and improve the network throughput.(2) According to the interference problem in channel assignment, this paper putforward a new Wireless Mesh Network multicast channel assignment algorithm.Traditional Mesh network channel assignment strategy is worked by assigningneighboring links different channels to reduce interference, but this approach cannotaccurately reflect the interference of the link. The proposed scheme analyzed in detailon interference that communication links have on channels, mainly include theinterference of links that use the same channel and use adjacent channels, alsoconsidered the data flow’s influence the link itself when choose the channel. Accodingto the links’ data flow to calculate the interference, through top-down traversalmethod, choosing channel which have minimum interference for link. Simulationshows that with the change of network size, the increase of the number of availablechannels and the increase of transmission rate, the network throughput of the schemehave been promoted, network performance is also improved.