A Research Of Low-complexity Detection Algorithm For DSM System

Differential spatial modulation(DSM)is a multiple input multiple output(MIMO)wireless transmission technique that achieves additional data bit transmission by utilizing antenna activation indexes.As a combination of spatial modulation(SM)and differential encoding,DSM share the sparse structure of the space time block(STB)of SM which has the merit that avoids the influence of interchannel interference(ICI)on DSM detection.In the meantime,the differential encoding of DSM allows the application of non-coherent detection in the receiver,which liberates the dependence of DSM on pilot sequences,thus avoids the extra cost of transmitting pilot sequences.At present,the problem that DSM system is faced with is the high detection complexity and the high channel environment requirements on detection.To solve the problems above,a novel low complexity feedback differential detection(LCFDD)method for reordered amplitude phase shift keying aided differential spatial modulation(RAPSK-DSM)is proposed which is based on the principle of DFDD.The proposed LCFDD method reduces the detection complexity by decomposing and pre-computing the DFDD detection process.Numerical analyses and simulation results show that the proposed LCFDD method is able to achieve substantial bit error rate(BER)performance improvement under fast fading channel conditions at the expense of low complexity.Next,LCFDD method is applied to space-time block coded differential spatial modulation(STBC-DSM)system,and its detection complexity is further reduced by using the low complexity symbol detection method.Finally,aiming at the problem that the conventional DSM transmission model is not accurate enough to describe the channel state in fading channels,this thesis proposes a modified DSM transmission model which describes the accurate value of the channel gain in each time slot of DSM block in fading channels.Based on this model,the proposed LCFDD method is improved to achieve better detection performance in fading channels.