Research On Coding-aware Routing Policy In Wireless Mesh Networks

Wireless Mesh Network(WMN),as a new type of multi-hop wireless network structure,has attracted widespread attention in academia due to its superior scalability and flexibility.At the same time,the concept of network coding changes the way of information exchange in the intermediate nodes of traditional routing.In the original storage-forwarding mode,network coding technology was added to allow network intermediate nodes to perform broadcast forwarding after data packets are encoded on the network,which effectively improve the transmission efficiency.The introduction of opportunistic routing has changed the way of selecting a single fixed transmission path in the traditional routing protocol,which using an alternative forwarding node set structure,providing more and better choices for the sending node to select the next hop forwarding node.This article mainly focuses on how to use network coding technology to improve network performance in Mesh networks.The main research results in this paper are as follows:(1)An on-demand wireless routing protocol LCR for encoding-aware load balancing is proposed.Through the analysis of COPE,the wireless routing protocol that uses network coding for the first time,there are two obvious defects in COPE routing: First,the route cannot actively detect the coding opportunities in the network and it can only be coded passively.Second,COPE limits the coding structure to two hops.COPE requires its coding structure to be within two hops,but it can still perform "opportunistic listening" and "decoding" operations at nodes that are two hops from the coding node.Aiming at the above two disadvantages,this paper proposes a new routing metric CLM,which not only extends the coding structure to more than two hops,but also makes it ?coding-aware? and also ?load-balanced? to avoid local congestion in the network.Using NS2 for network simulation,the routing protocol LCR is compared with the AODV and AODV+COPE protocols in scenarios with different data transmission rates and different numbers of data flows.The results show that the LCR routing protocol can effectively mitigate network congestion compared to the other two protocols,with higher network throughput and lower end-to-end delay.(2)An coding-aware opportunistic routing protocol LCOR is proposed.The use of the LCR coding aware load balancing on-demand wireless routing protocol proposed above can reduce the end-to-end delay of the network when the wireless link is relatively stable and the network structure changes little because the next node has been determined before transmission.However,when the nodes in the network change frequently,the fixed next-hop node may not be able to adapt to the frequently changing network.Different from the traditional route routing method,the LCOR opportunity routing protocol proposed in this paper adopts the structure of an alternative forwarding node set by using the broadcast mechanism of the wireless network,and allocates different priorities to the nodes of the candidate forwarding nodes.By assigning different priorities to nodes in the set of candidate forwarding nodes,it is decided which node to forward data as the next hop node.By using LCOR and CAOR routing protocols under different data stream sending rates and different numbers of data streams,simulation results using NS2 simulation software show that the code-aware opportunistic routing protocol LCOR can effectively improve network throughput.