Research On COPE-Based Joint Optimization Protocol Of Network Coding

Network coding can improve theresourceutilization ofmulti-hop wirelessnetwork andincrease thenetworkthroughput significantly.It is one of the research hotspots in recent years.Most of the studiesarefocused on finding a new network coding routing protocol or discuss the specific applications of wireless network coding.Most of the studies are based on ideal environmentwithout considering theinfluence ofnodes' transmissionpower/rate and coding combinationon theperformance of network codingin practical applications.There are somestudieswhich concerningthe optimization oftransmission power/rate in wireless network coding.Some of them study the optimization of transmission ratewhile ignoring the control of transmission power.Although some studies have proposedsome jointoptimization schemes oftransmissionpower/rate,but they did not take into account theoptimization ofcoding combination.For the lack of these studies,this paper proposes a joint optimization scheme oftransmissionpower/rate andcoding combination in wireless network coding.The main research contents are as follows:(1)The influence of transmission power/rate and coding combination on the network throughputis studied.Afteranalyzing the relationship between space-time efficiency and network throughput,anoptimization idea is proposed which can improve the network throughput viaa joint optimization scheme oftransmissionpower/rateandcoding combination.(2)Afteranalyzing the overhearing probability,thespace-time efficiency's calculation method is deduced byjointing theoverhearing probability.With the analysis ofspace which occupied by thecorresponding transmission power,the keyidea of transmission power selection is summarized.A rate selectionschemeis designedwhich choice the appropriate rate base on the transmission power and SINR.In addition,it is proved that the optimization of coding combination can further improve the network throughput.Thecorresponding optimal encoding combinationcan be achieved by the use of overhearing probability graph model.(3)Base ontheseanalyses,thejoint optimization scheme of transmissionpower/rate and codingcombinationisproposed.Finding the optimal transmissionpower/rate and coding combinationsis proved to be a NP-hard problem,sothe corresponding heuristic algorithm is designed to find the optimization transmission power/rate and coding combinations.(4)A new network coding protocolnamed PRCJO which combining the joint optimizationscheme and COPE is proposed.Thecorresponding packet header format is designed.And each node exchanges the state informationsuch as the packet delivery ratioto its neighboring nodes.In the final,the processing of packet is designed.Finally,simulation experiments results based on NS-3showthat,compared to the network coding protocol without joint optimization oftransmission power/rate and coding combination,the PRCJOcan further increase network throughput and reduce the retransmission of data packets.