Research On Beamforming Algorithms In Lte-A And Implementation On Fpga

The downlink beamforming technology is used to improve the system capacity, spectral efficiency, and users’SINR, solve dense urban capacity bottlenecks and suppress interference signals in LTE-Advanced system. LTE-A standard uses precoding based on codebook, which can be called a beamforming algorithm based on codebook in broadest sense. It must send PMI and feedback.This article discusses the beamforming algorithm based on the decomposition of channel correlation matrix, channel SVD decomposition and codebook. In order to verify the performance of the three algorithms, LTE-Advanced link level simulation platform is built, in which the three algorithms are simulated and analysed according to3GPP R11Agreement version.The results show that:when the channel is VehA or PedB, the performance of the beamforming algorithm based on codebook is better than the beamforming algorithm based on the decomposition of channel correlation matrix and channel SVD decomposition; when the channel is Gauss, the performance of the beamforming algorithm based on the decomposition of channel correlation matrix and channel SVD decomposition are better than the beamforming algorithm based on codebook, and the two beamforming algorithms don’t need to send PMI and feedback,but the beamforming algorithm based on channel SVD decomposition will increase the complexity of the system.On the basis of the performance analysis of the three algorithms, the beamforming based on SVD decomposition is implemented by using FPGA in this article. According to the detailed derivation of the SVD decomposition process of2×2complex matrix, system implementation using FPGA is divided into delay module, complex multiplier module, Rec to Polar module, Polar to Rec module, ArcTan module and Right Rotation module. The function of the main modules is described and tested. The entire system is simulated. According to the comparison of the simulation data obtained by using FPGA and the data obtained by using MATLAB, the whole design system is verified to be correct.