Signal Detection Algorithms Based On SVD In SM System

Multiple-input Multiple-output(MIMO)is a transmission technique in which there are multiple antennas in both of the transmitter and receiver,of which spatial modulation(SM)was recently proposed and it has many advantages,so that it attracted much attention.Compared to traditional MIMO systems,it makes uses of space dimension and activates only one antenna to transmit data symbol at each time slot.Thus,inter channel interference(ICI)and inter-antenna synchronization(IAS)can be completely avoided.Meanwhile,transmitting a part of information data through the selection of the activated transmit antenna ensures a certain spectral efficiency.Besides,the complexity of the detector is reduced as well.Therefore,SM is more suitable for unbalanced MIMO systems in which the number of receiver antennas is smaller than that of transmit antennas.This paper focuses on the research of detection algorithms for SM system.Firstly,the paper makes a study about the classical detection algorithms of SM and analyzed its advantages and disadvantages.Of which M-SVD is a modified algorithm of Signal vector based detection(SVD),and it introduces the idea of candidate antennas to improve its BER performance.This paper further analyzed LC-SVD algorithm,then,R-SVD algorithm is proposed to reduce its complexity.R-SVD algorithm uses the idea of sphere decoding(SD)by reducing the times of searching.Simulations show that the proposed algorithm can achieve the same bit error rate performance with original algorithm with lower complexity.Moreover,by further mathematical formula derivation,the activated antenna index detection can also be modified using the nature of constellation point,then MPSK-SVD algorithm is proposed for multiple phase shift keying modulation(MPSK).Simulations show that the proposed algorithm can offer a better bit error rate performance gain compared to the original with the same number of candidate antennas.With the same number of transmitting antennas,generalized spatial modulation can achieve higher spectral efficiency compared to spatial modulation,besides,the number of transmitting antennas is not limited to a power of two,so the above two algorithms are applied to GSM system,simulations show that they can also have a good performance in GSM system.