Signal Detection Based On QR Decomposition Algorithm In MIMO System

The receiver and the transmitter of the MIMO system require a good signal combination and detection capability, and the theoretical channel capacity can be approximated as the number of transmit and receive antennas grows linearly. Vertical hierarchical space-time code VBLAST is a typical representative of MIMO system space-time multiplexing technology, in the Rayleigh smooth channel conditions, with a high transmission capacity and spectrum utilization.Based on the algorithm of detection performance and computational complexity of compromise, has always been the focus of scientific researchers. Reducing the computational complexity and improving the performance of the system are of great significance to the application of MIMO systems. The MIMO system signal detection algorithm, mainly divided into non-linear detection and linear detection algorithm, for the traditional algorithm, the nonlinear detection algorithm is superior to the linear detection algorithm, but it often increases the complexity of the algorithm. The main contents and contributions of the paper are as follows:First, this paper proposes a decision-based QR decomposition detection algorithm, which uses shadow area constraints to enhance the interference cancellation, effectively reducing the impact of error propagation, while ensuring a relatively low algorithm complexity. Through numbers of candidate point feedback can effectively suppress the error in the detection process throughout the detection process and improve the performance of the algorithm.Secondly, On the basis of the above derivation, the RC-QR detection algorithm based on the ML criterion is proposed. The QR decomposition algorithm first detects the existence of the error in the layer signal estimation, which will directly affect the signal estimation of all subsequent layers. In order to improve the performance of the proposed algorithm, this paper improves the performance of RC-QR algorithm at the expense of some complexity.Thirdly, in the QR decomposition algorithm, different channel ordering will result in different Q and R matrices. The optimal sorting of the first detection signal is used as the sorting of the subsequent detection. If the channel is changed, the optimal ranking is re-selected,and the performance is improved while reducing the complexity,thusan iterative update sorting scheme is proposed.Fourth, the proposed signal detection algorithm is applied to STBC and VBLAST combined MIMO systems. The coding scheme can improve the diversity of each layer and improve the performance of the system, and reduce the complexity of QR decomposition in LSTBC system.