Research On Multicast Routing And Channel Assignment Algorithm For Wireless Mesh Networks

Wireless mesh networks(WMNs)is next-generation wireless network for wireless broadband access which can effectively solve the “last mile” Internet access problem.Adjacent link transmitting packets simultaneously will cause the interference.The capacity will reduce due to the interference in WMNs.Multicast is a type of communication that the packets transmitted by the source node can be received by a set of receiving nodes simultaneously and there is no interference among the nodes that receive packets from the same node.This characteristic of multicast is called wireless broadcast advantage(WBA).Multicast can save more bandwidth than unicast because of WBA.Therefore,multicast communication is one of the key technologies to improve the network capacity which has attracted much attention from academic community.In order to achieve effective multicast communication,reasonable routing paths should be established between all the multicast receiving nodes and the multicast source node,and then appropriate channels are assigned to these paths to ensure that the nodes can communicate with each other.Multicast routing can choose the best paths between source node and destination nodes and construct multicast tree with less interference.Channel assignment can assign reasonable channels for the nodes in the multicast tree to futher reduce the interference and improve the network performance.Therefore,designing better multicast routing and channel assignment algorithm for WMNs has important research significance in reducing network interference and increasing network capacity.Although there are some outcomes about multicast routing and channel assignment for WMNs,still exists some problems: most works exploited protocol interference model or two-hop interference model to measure interference in multicast communication,which were too simple to describe interference precisely;only the interference was considered in multicast routing,ignoring the influence of the number of links;in the process of channel assignment,the objective was minimizing the interference,but the channel congestion could also influence the performance of network.Aiming at the existing problems,the multicast routing and channel assignment for WMNs are researched in this paper.The main innovations are as follows:(1)The interference power is used to measure the interference accurately and is taken into consideration in the process of both multicast routing and channel assignment.A multicast routing algorithm called interference power and load balance(IPLB)and an interference power-based multicast channel assignment(IPMCA)are proposed which are combined as IPLB_IPMCA algorithm to be illustrated in this paper.IPLB combines the load of nodes,interference power and the number of links to find the reasonable routing paths between the source node and the destination nodes in order to reduce interference and balance the load of the network to construct an effective multicast tree.The channels are assigned for the nodes in multicast tree through IPMCA.According to the descending order of the interference domain load of nodes,IPMCA assigns the channel with minimum interference power load for the nodes to further reduce network interference and improve network performance.(2)The influence of channel congestion for network performance is considered in this paper and the channel load is used to measure the channel congestion.A channel assignment algorithm called joint interference power and channel load(JIPCL)is proposed.The interference power-load weight factor is proposed to evaluate the importance of nodes in network,as the priority.The interference power load and channel load are considered in JIPCL to assign the channels with minimum interference power load and channel load for the nodes according to the descending order of the priorities.The MATLAB is used to get the results of multicast routing and channel assignment.Then put the results into the NS-3 to simulate the network performance.The simulation results show the proposed algorithms can achieve better network performance of WMNs.