Research On MIMO Receiving Technology Based On TR-STBC ZP-OFDM

With the increasing demand for communication,for some special scenarios,such as emergency communication,war and military scenarios,a communication solution that can support long-distance or ultra-long-distance is required.Under this background,scattering communication technology with strong anti-jamming capability has become one of the key research objects.However,there are multipath effects and Doppler effects in the scattering channel,which will greatly affect the transmission signal with the increase of the communication rate.The combination of Orthogonal Frequency Division Multiplexing(OFDM)technology and Multiple Input Multiple Output(MIMO)technology can effectively improve the capacity and frequency band efficiency of wireless communication systems,as well as improve communication network systems.quality of service.Because ZP-OFDM uses zero suffix as guard interval,it has lower transmit power and better system performance than CP-OFDM.Time-Reversal Space Time Block Coding(TR-STBC)can not only effectively resist intersymbol interference in frequency selective channels,but also recover Space Time Block Coding(STBC)losses multipath diversity.Aiming at the background of scattering communication,this paper studies the combination of TR-STBC and ZP-OFDM.For the scattering communication system,this paper introduces the FWFT transform into the ZP-OFDM system,and designs a ZP-OFDM transmission scheme based on the FWFT transform.The sparseness and block-diagonal structure of the FWFT transform can effectively reduce the superposition of sub-carriers,thereby reducing the peak power of the transmitted signal,and significantly reducing the system peak-to-average ratio and bit error rate.At the same time,the FWFT transform replaces the FFT transform,so that the system has lower complexity and better bit error performance.In addition,this paper also extends the FWFT transform to STBC-OFDM and TR-STBC-OFDM systems,and also obtains lower peak-to-average ratio,lower complexity and better bit error performance.Channel State Information(CSI)is the time-varying prior reliability information before the receiver makes a decision,and is a dynamic monitoring of channel changes.Due to the frequency selectivity and time variability of the scattering channel,the transfer function of the channel shows non-uniform characteristics in both the time domain and the frequency domain.Therefore,the amplitude and phase of different sub-carriers are different,resulting in different sub-carriers.The credibility is not fair.Therefore,it is necessary to obtain CSI before soft-decision decoding is performed on the received signal of the OFDM system.However,the CSI extraction method of the traditional CP-OFDM system is not applicable to the ZP-OFDM system.In order to make the decision of ZP-OFDM system fairer and further improve the performance of the system under scattered channel,this paper presents a CSI extraction method for ZP-OFDM system,and generalizes it to TR-STBC-OFDM and TR-STBC-FWFT-In the OFDM system,the system performance is effectively improved by extracting CSI and using it to compensate the equalized signal at the receiving end.