Multi-user Multi-stream Hybrid Precoding with Hybrid Dynamic Connection Structure

Hybrid precoding is essential to improve the performance of multi-user millimeter-wave massive Multiple Input Multiple Output (MIMO) systems, but currently hybrid precoding based on fully connected structures and sub-connected structures have the problems of high energy consumption and severe performance loss, respectively. This paper comprehensively considers the spectral efficiency and energy efficiency of the system, proposes hybrid dynamic connection structure, and designs hybrid precoding algorithm under the structure. In this algorithm, the analog domain precoding of the hybrid dynamic connection structure is designed by maximizing the increment of Signal-to-Interference-plus-Noise Ratio (SINR), and then the digital domain precoding is designed by Block Diagonalization (BD) to suppress multi-user multi-stream interference through an equivalent channel. Simulation experiments show that the spectral efficiency of the proposed hybrid dynamic connection structure is between the spectral efficiency of the fully connected structure and the spectral efficiency of the hybrid fixed connection structure, but the highest energy efficiency is obtained.