A Study On Network Coding-aware Routing Algorithms For Wireless Multi-hop Networks

In 2000,network coding theory was first proposed by Ahlswede et al.It's a new type of data transmission,and allows the intermediate nodes to encode the incoming packets before forwarding.it can increase the amount of information in single forwarding and improve network throughput.But in the data transmission process,we found the network coding opportunities have not been the maximum used.In the routing establishment process,coding aware technology can take coding opportunity into account,by actively exploring,creating and use the potential of the coding opportunities,so that the network throughput has been further improved.Coding aware technology can efficiently improve the performance of the network by applying in the wireless multi-hop network.This thesis is based on the network coding aware routing algorithms for wireless multi-hop network,and the main research content include two aspects: firstly,node network coding aware opportunistic forwarding routing protocol for wireless multi-hop network;secondly,network coding-aware multi-path routing in wireless multi-hop network.The achievements of this thesis include the following two aspects:Firstly: The existing coding-aware routing protocols may have the problems of misjudging coding opportunities under unstable link state and requiring exchanging huge packets information in selecting the optimal coding node from forwarder set which could lead to large end-to-end delay and high network overhead.To solve these problems,a node network coding aware opportunistic forwarding routing protocol(NAOFP)is proposed by this paper.By introducing several mechanisms of adding additional ID based on high probability of intercept,the optimal forwarding node selection in forwarder set and the interception cache of packets.Simulation results by using OPNET show that NAOFP has a better performance in network throughput,end-to-end delay and the probability of decoding.Secondly: To solve the problems existing in the present multi-path routing based on network coding-aware,including it doesn't consider that the rate of data flow through the coding node maybe not match when carry out data flow distribution,which leads to declining coding performance and raising delay,and COPE scheme used in CAMP can't find coding opportunities beyond the two-hop range,which makes coding opportunities can not get fully utilized,a rate adaptive coding-aware multipath routing protocol(RACMP)is proposed by this paper.By taking into account the rate of the data flow through the coding node to realize a greatest data rate matching when allocate the data flow,which improves the coding performance obviously,and expanding the search scope of the coding opportunities by using an inter-flow coding opportunity judge rule.Simulation results by using OPNET show that RACMP has a better performance in network throughput and the proportion of encoded packets,it also reducing the average latency of data transmission.Finally,we have the conclusion about this thesis and further research directions are given.