Detection Algorithm Research For Quadrature Spatial Modulation System

Although MIMO technology has advantages of high spectral efficiency and high reliability,there are also exists inter channel interference(ICI),inter antenna synchronization(IAS)is difficult,high receiver detection complexity and multiple antenna radio frequency(RF)links cause high cost and overhead.The emergence of the spatial modulation(SM)technology solved the problems mentioned above,but its spectrum efficiency and bit error performance still need to be improved.The quadrature spatial modulation(QSM)technology not only can effectively improve the spectral efficiency of the SM technology,but also can avoid ICI,reduce IAS requirement,reduce receiver detection complexity and the link cost.This thesis focuses on researching the detection algorithm of the QSM system,the main contents of this thesis are as follows:1.The traditional linear detection algorithm zero forcing(ZF)detection and minimum mean square error(MMSE)detection are applied to the QSM system.It is founded that two linear detection algorithms are simple and easy to implement and has low complexity,but the bit error performance is poor.Aiming at the problem of poor performance of the traditional linear detection algorithm,an enhanced zero forcing detection algorithm based on the ZF detection is researched in this thesis,this scheme introduces iterative idea.Monte Carlo simulation results show that the detection scheme not only has significantly improved bit error performance over traditional ZF detection scheme,but also the computational complexity is still much lower than the maximum likelihood(ML)optimal detection scheme,just slightly higher more than the ZF detection algorithm.2.As far as QSM system is concerned,although the existing detection algorithms in the QSM system can be applied to the MPSK signal,there is no specific algorithm based on the constellation characteristic of the MPSK signal.Based on the characteristic of MPSK signal constellation,the idea of ML quantization demodulation is adopted in thesis,first detects the modulation symbol,and then detects the activated antenna combinations,and researches an improved maximum likelihood detection scheme for MPSK signal.The Monte Carlo simulation results show that the researched improved maximum likelihood(IML)detection scheme not only has better bit error performance,but also the computational complexity is significantly lower than the ML detection algorithm.What's more,the computational complexity of the IML scheme is independent of the modulation order,and the higher the order,the better its advantages in the low complexity relative to the ML detection scheme.