Research On Network Coding Technology In UAV Cooperative Communication

In the situation of complex modern warfare tasks,single UAV is increasingly unable to meet the operational requirements.In order to achieve long-distance,large-capacity data transmission requirements,UAV cluster operations will become the main form of military UAV applications in the future.UAV cooperative communication is the premise and important guarantee for command and control,reconnaissance information return and battlefield situation awareness.In cooperative communication,UAV is regarded as signal source node or relay node,which is very similar to the simplified network coding structure,therefore,it is considered to combine the two technologies for information transmission.Applying network coding to UAV cooperative communication,and using the computing power of network coding to optimize the network structure of the cooperative communication system,improve throughput and data transmission security.Therefore,the application of network coding in UAV cooperative communication has theoretical research value and practical application prospect.Firstly,according to the two typical scenarios in UAV cooperative communication,the irregular topology structures suitable for line-of-sight and non-line-of-sight scenarios are proposed separately.The basic principles of traditional network coding,linear network coding and complex domain network coding are studied,the process of information transmission and processing is deduced,and the timeliness of each scheme is evaluated.Aiming at the inapplicability of traditional network coding structure in UAV cooperative communication,two kinds of irregular topology structures suitable for line-of-sight mode and non-line-of-sight mode are proposed.The theoretical analysis and simulation results show that applying irregular topology to UAV cooperative communication,while ensuring the efficiency of information transfer,there is also a significant advantage in accuracy.Secondly,the information transmission scheme under the line-of-sight mode is studied.The signal transmission process based on irregular topology structure in line-of-sight mode is deduced,the signal transmission is modeled by using MATLAB software,and the influence of the number of sources and relays on the system performance is discussed.Combining complex domain network coding and typical data chain coding and modulation system,complex domain network coding combined with "convolution coding+BPSK modulation" scheme," Binary Low Density Parity Check(Binary LDPC)coding+QPSK modulation" s cheme,"Quaternary LDPC coding+QPSK modulation" scheme are designed.After evaluating the symbol error rate and throughput performance of each scheme,analyzing effectiveness and reliability of the system comprehensively,the scheme of "Quaternary LDPC coding+QPSK modulation" is selected.Finally,the information transmission scheme under non-line-of-sight mode is studied.The signal transmission process based on irregular topological structure in non-line-of-sight mode is deduced,the signal transmission is modeled by using MATLAB software,and the influence of the number of sources and relays on the system performance is discussed.Combining complex domain network coding with typical data chain coding and modulation system,the scheme of "turbo+BPSK modulation","Binary LDPC coding+BPSK modulation" and "RA+BPSK modulation" are designed.After evaluating the symbol error rate and throughput performance of each scheme,analyzing the effectiveness and reliability of the system comprehensively,and the "Binary LDPC coding+BPSK modulation" is selected for the information transmission.