| To meet the requirement of future mobile communications, the work on wireless communication systems strives for higher data rate all along. The key of research challenge is to find a multi-antenna transmission technology. Multiple input multiple output (MIMO) technology has been considered one of promising techniques due to the fact that it can full use of multiplexing gain and space diversity gain to achieve high data rate and reduce bit error rate. Also, MIMO does not scarify extra transmission power and bandwidth. Considering that the available MIMO has many problems caused by inter-channel interference and synchronization between the transmitting antennas, a spatial modulation system was presented. On the basis of the fifth generation of mobile communication system, in order to achieve better multi-antenna transmission, a more in-depth study was carried out in the spatial modulation technology in the paper, mainly as follows:Firstly, detailed analysis the spatial modulation of several traditional detection algorithms, including maximum likelihood (ML) detection algorithm and block ordering minimum mean square error (OB-MMSE) algorithm. Maximum likelihood detection offers the optimal performance while it encounters great difficulties in practical system because of its computational complexity, which is increased exponentially with the number of antennas and constellation points. The block ordering minimum mean square error (OB-MMSE) algorithm has low complexity, but in high dimensional transmit antenna detection relatively poor performance, its detection performance has a substantial margin. Owing to the shortage of this two algorithms, introduced the lattice reduction aided technique and LLL algorithm aided the linear detection algorithm and the nonlinear detection algorithm, which can obviously improve detection performance of theses suboptimum and low computational complexity detection algorithm. Therefore, dealing with these shortcomings, this paper proposes two new algorithms. The one is a novel lattice reduction aided detection algorithm in spatial modulation system, which can effectively improve the performance and reduce the computational complexity of the spatial modulation system in the high-dimensional transmit antenna. Other one is computationally efficient concentrated ML(CECML-OB-MMSE) algorithm which enables efficient computation of a newly proposed ordering metric for the OB-MMSE detector in a GSM system. The proposed algorithm avoids redundant computations and enables early termination without noticeable performance degradation. These two improved detectors are designed by combining different methods which can achieve good tradeoff between detecting performance and complexity.Secondly, stress is put upon the simulation study of the improved detectors’ error performance. This thesis firstly compares the bit error rate (BER) of traditional detections’performance through simulation results, with different algorithms, various numbers of transmitting antennas and receiving antennas and different modulations environment. These simulations provide data supports for the following improved algorithms. And then simulation comparison and complexity analysis are carried to improved detectors. Simulation results and academic analysis verify the correctness of the conclusions about two improved detectors which have certain reference value and great relevance to applications in signal processing of SM spatial multiplex system:the detection performance of the lattice reduction aided detection algorithm is superior than OB-MMSE algorithm and close to maximum likelihood detection, meanwhile it has lower complexity; With the proposed CECML, more than 50% of the complexity of OB-MMSE at sufficiently high SNR can be reduced without noticeable performance degradation, which clearly shows the efficiency of the proposed algorithm. Both improved algorithm scheme has good reference value and the actual space modulation signal processing. |
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