Research On Orthogonal Time-Frequency Space Modulation And It's Multiple Access Technology

Since the 1990 s,the mobile communication service has been rapidly developed,the mobile communication system in interpersonal communication,information transmission and the demand of other appects is more and more urgent,the quality of system communication requirements are also more and more high.The new generation of wireless communication technology needs to meet people's communication needs in all kinds of scenarios.Orthogonal Time Frequency Space Modulation is a new Modulation technology proposed in recent years.This Modulation method finds the Time domain Modulation and Frequency domain Modulation convergence point,can get good performance gain.Based on this background,the orthogonal time-frequency spatial modulation system and some of its key technologies are studied in this thesis.First of all,this thesis introduces the development history of wireless communication,introduces the high-speed scene of communication technology related research and analysis of the research significance of the thesis,introduces the relevant research status at home and abroad,and then the thesis involved in the relevant communication knowledge for a brief description.Secondly,considering the serious impact on signal transmission in high-speed mobile communication scenarios,this thesis studies and analyzes the orthogonal time-frequency spatial modulation technology and its system model,and compares it with orthogonal frequency division multiplexing technology.The orthogonal time-frequency spatial modulation system model needs to embed a layer of discrete Fourier transform on the basis of the traditional orthogonal frequency division multiplexing system model,through which the transmitted signals in time-frequency domain can be transformed into signals in time-delay Doppler domain.This thesis analyzes the influence of delay Doppler frequency on signal transmission,and then introduces the discrete Fourier transform and derivation of relevant formulas,and then analyzes the system model of orthogonal time-frequency space modulation and derivation of orthogonal time-frequency space modulation input and output matrix expression form.Then the orthogonal time-frequency spatial modulation system model is simulated and analyzed at different speeds.The results show that the orthogonal time-frequency spatial modulation system has better bit error rate performance.Finally,for the problem of multiple access of orthogonal time-frequency spatial modulation system requiring insertion protection interval,two kinds of multiple access schemes without insertion protection interval in time-frequency domain are presented in this thesis: continuous and staggered.In this thesis,the system model of uplink scenario based on OTFS technology is analyzed at first,and then the continuous time-frequency multiple access scheme is proposed,and then the cross-time-frequency multiple access scheme is proposed to improve the multi-access scheme.After that,the thesis compares and analyzes the two multiple access schemes,and compares the performance of the two algorithms through simulation.The simulation results show that the staggered multiple access scheme is better than the continuous multiple access scheme.