Method For Discovering Network Coding Opportunity In Wireless Networks

Network coding is a new kind of data transmission mode. It can potentially provide significantthroughput benefits by encoding packets from different flows into a single mixed packet via algebraicoperations prior to forwarding them. In wireless Mesh network, the throughput can be substantiallyimproved by network coding because of the unreliability and broadcast nature of the physical layer.However, wireless network throughput is limited to the coding opportunity of the intermediate node innetworks.Firstly, this paper studies the effect of coding opportunity on the network throughput in COPE. Theperformance of COPE by simulation in NS-2is evaluated. In the following, the paper focuses on theresearch of the method for discovering network coding opportunity in Mesh network from two aspects.1. The recent research about the network coding technology in improving the performance of wirelessMesh networks is analyzed. A common problem of these network coding schemes is that the decodingoperation may fail. A coding packet will be dropped immediately when it can’t be decoded, which is awasted transmission opportunity. The decoding failure which seriously affects the network throughput iscaused by error coding opportunity detection. Based on the existing network coding schemes, a codingopportunity detection algorithm is proposed. In this algorithm, relationships between nodes in localtopology provide necessary conditions for the judgment of coding opportunities. In the process oftransmission, information in packet is used to judge whether the packets has changed. The proposedalgorithm can effectively detect the coding opportunities by combining the two aspects. The simulationresults show that the proposed algorithm can effectively improve the accuracy of coding opportunitydetection.2. The multi rate network coding schemes are studied. Multi rate leads to the varying number ofpackets coming from different sources obvious distinct. That will affect the network coding opportunities atsome point. A kind of minimum delay cost network coding method is presented. The method uses the delaysending strategy to wait for the coding opportunity. The simulation results show that the method canincrease the network coding opportunities effectively.