Research On High-Diversity Space-Time Coding For Spatial Modulation Systems

Due to the limitations of single antenna transmission technology in terms of spectrum efficiency and channel capacity,Spatial Modulation(SM)technology has become a hot research direction.Although SM improves spectrum efficiency,it does not consider performance optimization.In order to improve communication reliability,SM combined with Space-Time Block Coding(STBC)not only ensures higher spectral efficiency,but also provides transmission diversity.Taking advantage of the advantages of STBC-SM,this thesis combines STBC with two extension technologies of SM,and proposes two kinds of space modulation schemes of full diversity space-time coding under the transmission of multiple antennas.1.A space-time coding scheme for rotating STBC-SM(RSTBC-SM)is proposed based on space modulation technology.The traditional STBC-SM scheme,which combines space-time block code with space modulation,can achieve higher diversity gain,but it can not achieve full diversity at high rate when the transmitting antenna is larger than 2.In order to achieve full diversity of multiple antennas,the symbol matrix of RSTBC-SM scheme uses quasi-orthogonal STBC structure to achieve higher diversity gain.The theoretical analysis proves that the scheme satisfies full diversity and the rate is higher than that of traditional STBC-SM scheme.In terms of performance analysis,RSTBC-SM scheme is superior to traditional STBC-SM scheme gradually with the increase of signal-to-noise ratio due to its higher diversity gain.Moreover,RSTBC-SM scheme has higher coding gain and better bit error rate than DS-SM scheme.Finally,a new full diversity space-time coding scheme is proposed by compromising the spectral efficiency and coding complexity.2.A new full diversity differential space modulation(LSTBC-DSM)scheme is proposed.Differential Spatial Modulation(DSM)makes use of differential encoding based on SM to make the detection process without channel state information.Subsequently,FE-DSM and other schemes can achieve full diversity gain in the case of multiple antennas,but because each time block can only send one information symbol,it can not improve the spectral efficiency.Based on the full diversity differential spatial modulation scheme proposed in this thesis,the precoding rotation matrix is used to transmit multiple information symbols in one time block.Compared with the traditional differential space modulation scheme,the spectral efficiency of this scheme is significantly improved.The simulation results show that the proposed scheme has the same BER slope and diversity gain as FE-DSM scheme and full diversity space-time coding scheme under the same spectral efficiency.Compared with the proposed full diversity space-time coding scheme,although some performance is lost,the receiver can not need channel state information.