Research On Non-orthogonal Multi-carrier Transmission Technology In Satallite-to-slot Downlink

With the increase of people's demand,wireless communication technology has developed rapidly in recent years.As a result,the development of communication technologies has led to the appearance of various mobile terminals.Additionally,in consideration of various emergency communication scenarios and the increasing demand of people,satellite communications will inevitably play an irreplaceable role in future communication systems.The increase in the number of terminals and communication needs will undoubtedly put even greater pressure o n the limited spectrum resource.Therefore,the search for more efficient spectral communication technology has become the focus of some researchers' attention.The paper takes the satellite downlink as the background,aiming to introduce high spectrum frequency division multiplexing(SEFDM)technology into satellite communications system to improve spectrum utilization.Firstly,since both SEFDM and OFDM are multi-carrier signals,which have the same high Peak-To-Average Power Ratio(PAPR),it will cause some difficulties in signal transmission.Therefore,the analysis of the reasons for the low PAPR performance and the PAPR suppression algorithm of the SEFDM signal are studied in this paper.By studying the PAPR suppression algorithm in the traditional orthogonal frequency division multiplexing signal,the PAPR suppression algorithm suitable for the SEFDM system is further proposed to redu ce the cost of the transmitter equipment.The simulations verify the performance of the algorithm and the influence that the algorithm bring about to the system's BER performance.In addition,the severe Inter-Channel Interference(ICI)carried by the SEFDM signal itself poses a great challenge to the system receiver design.Aiming at the fundamental reason of the low BER performance of SEFDM system,the paper designs a low-complexity system detection algorithm,an optimized system detection algorithm and a high-performance hybrid detection algorithm.With the support of these algorithms,the system can obtain excellent BER performance with lower computational complexity.Finally,the paper designs two kinds of receiver front-end processing schemes under the Lutz channel model,so that the classical detection algorithm can be applied in the satellite-to-earth complex channel.Two link schemes of joint sender and receiver are designed,and the performance of the proposed scheme s are verified by simulations.The simulation results show that the designed symbol generation scheme can greatly suppress the PAPR of the signal.The low complexity detection algorithm and hybrid detection algorithm have excellent detection performance.The simulation results show that under the scenario involved,the transmitter and receiver modules proposed in the paper can support the system operation well.