Research On Channel Allocation And Routing Protocol In Multi-interface And Multi-channel Wireless Mesh Networks

Wireless Mesh network(WMN)is a multi-hop network with flexible networking and high network coverage.Channel allocation and routing protocol optimization can improve network performance,which are two important research contents in WMN.In a multi-interface and multi-channel wireless Mesh network,the number of interfaces on a node is not equal to the number of channels.Therefore,this paper needs to solve the problem of load balancing under the condition of satisfying the connectivity of the network,while considering the decrease of network efficiency and throughput caused by too frequent channel switching.In terms of routing protocols,since traditional routing protocols do not make full use of the broadcast characteristics of the network,this paper will make improvements based on opportunistic routing protocols,considering how to select forwarding nodes more reasonably and reduce the coordination overhead between nodes while reducing the expected transmission times.In view of the above problems,in the multi-interface and multi-channel wireless Mesh network with large network topology changes,this paper studies channel allocation and routing protocol.The main innovations are as follows:1.A multi-interface and multi-channel allocation algorithm(DACA-LB)is proposed.In this algorithm,static interfaces and a dedicated channel are set up to ensure network connectivity between neighbor nodes.Secondly,the maximum interface load threshold is calculated based on the queue load and the utilization of CPU,memory,and network.When the queue load exceeds the threshold,the interface is dynamically switched to another interface to perform transmission tasks to achieve load balancing among interfaces.Finally,the interference of each channel is calculated according to the channel allocation algorithm,and the queue will select the channel with the least interference for transmission.The algorithm is compared with end-to-end load-aware channel assignment(ELIA)and load-balance and interference-avoid channel assignment(LBOA-OCA),the experimental results show that DACA-LB algorithm improves network throughput and reduces average packet loss rate by channel allocation based on interface load balancing.2.A new routing metric PTD(Probability Transmission Distance)is proposed,which comprehensively considers the physical distance between nodes and the probability of link transmission.Based on this,a opportunistic routing algorithm based on probability transmission distance(ORPTD)was proposed.Firstly,ORPTD finds all the neighbor nodes that are closer to the destination node than the source node according to the physical distance between the nodes,and calculates the PTD between the source node and the neighbor node,and determines the candidate node set according to PTD.Secondly,the remained probability transmission distance between the candidate node and the destination node is calculated.Then,the total probability transmission distance between the source node and the destination node can be obtained,and the corresponding ordered candidate node set can be obtained by sorting them.The source node selects the candidate node with the highest priority to send packets,thus reducing the expected transmission count.Comparing this algorithm with four candidate nodes selection algorithms such as extremely opportunistic routing(Ex OR)and opportunistic any-path forwarding(OAPF),the experimental results show that ORPTD algorithm can determine the candidate nodes set in a short time and minimize the expected transmission count.