Research On Low Complexity Signal Detection Algorithms For SM-MIMO Systems

MIMO system brings gain to the wireless communication system, but also, the problems of channel interference, synchronization between the antenna and the expensive multi-RF chains are introduced. Spatial modulation(SM) system as a new MIMO transmission techniques have been proposed. The antenna of Spatial modulation as a carrier is activated to transmit information. Spatial modulation effectively simplify the traditional MIMO scheme channel interference between the antenna, RF expense and other synchronization problems. At the same time, the number of Spatial modulation applied to the antenna for uplink and downlink MIMO channel mass asymmetry. In order to make Spatial modulation system used better in practice, low-complexity detection algorithm has been a hot topic. This paper mainly studies of low-complexity detection algorithm for Spatial modulation system.Firstly, based on the study of the classic detection algorithm for Spatial modulation system, a kind of second-order detection algorithm based on Signal Vector Based Detection(SVD), SVD-Maximum Likelihood(SVD-ML) detection algorithm, is proposed. The algorithm overcomes the disadvantage that the SVD detection algorithm can achieve the optimal performance only in the Spatial modulation system with low-order modulation. At the same time, This algorithm makes the search space of ML detection algorithm become smaller. Thereof, the complexity of SVD-ML detection algorithm is reduced.Secondly, The tree-search detection algorithm of Spatial modulation system is studied. In terms of depth-first search detection, Receiver-centric Sphere Detection(Rx-SD) algorithm and Transmit-centric Sphere Detection(Tx-SD) algorithm are analyzed. By sorting the Rx-SD algorithm in the search tree layer to speed up the convergence of the search path. so, the complexity of the algorithm is further reduced. In terms of breadth-first search detection, M-algorithm to Maximum Likelihood(M-ML) detection algorithm and its improved algorithm are studied. The M value of each layer in improved M-ML detection algorithm search tree is not a fixed value. The M value with the layer of the search tree gradually reduce. Thus, the complexity is further reduced.Finally, detection algorithm for Generalized spatial modulation(GSM) system is studied. The optimal detection algorithm and some classical low-complexity detection algorithms for Generalized spatial modulation system are analyzed, respectively. At the same time, the sphere detection algorithm of GSM system is studied. And the improved sphere detection algorithm is given.