Research On Universal Filter Multi-carrier Technology In Non-terrestrial Network Scenarios

With the rapid development of mobile communication in recent decades,the era of 5G has arrived.The terrestrial mobile communication system can meet the majority of users' requirements,but cannot meet the requirements of scenes like oceans and sparsely populated land.The existence of non-terrestrial network(NTN)can fulfill the application scenario requirements of the terres trial mobile communication system.Therefore,it is of great significance to study the integration of the two,which is also the next research direction of mobile communication system.The advantages of NTN low orbit satellite communication system,such as low time delay and low power consumption,make the research on the fusion of low orbit satellite communication system and terrestrial communication system become the key research content.However,the large carrier frequency offset(CFO)of low orbit satellite communication system is unavoidable.Compared with orthogonal frequency division multiplexing(OFDM)technology,universal filter multi-carrier(UFMC)technology has strong anti-carrier frequency offset characteristics,and is also one of the candidate waveforms of 5G.Therefore,this waveform technology is a highly competitive waveform scheme for satellite and land fusion.This paper mainly includes three parts: NTN low-orbit satellite communication scenario channel research and modeling;Performance study of UFMC system under ideal synchronization condition;Performance study of UFMC system under CFO condition.Firstly,the NTN low-orbit satellite channel in TR 38.811 specification published by 3GPP is studied.After the channel influencing factors are introduced,the common tapped delay line model is studied,and the time-varying tapped delay line model is used to model the low-orbit satellite channel of NTN.After introducing the basic principle of UFMC technology,the time-frequency characteristic of UFMC signal is analyzed and the filter is studied.These contents lay the foundation for the follow-up research.Secondly,the error performance of UFMC technology and DFT precoding UFMC technology in additive gaussian white noise channel and frequency-selective fading channel is deduced and verified theoretically,and the error performance of the two technology in dual selection channel under different conditions is studied.In addition,in order to comparative study the performance of UFMC systems,The signal characteristics of UFMC,OFDM and their DFT precoding schemes,such as out-of-band leakage and peak to average power ratio,as well as their error performance in different channels under ideal synchronization,are studied.Finally,the error performance of UFMC,OFDM and their DFT precoding schemes under different channels under the condition of CFO is studied.The CFO of low orbit satellite communication system is inevitable,and its existence is beyond the maximum range that mobile communication s ystem can accept.Therefore,aiming at the low-orbit satellite communication scenario of NTN,the estimation technology of CFO in the frequency domain is studied,and compares the estimation performance of the preamble-based estimation method,the pilot-based estimation method and the improved preamble-based estimation method.