Hybrid precoding is an indispensable technique to harness the full potential of a multi-user massive multiple-input, multiple-output (MU-MMIMO) system. In this paper, we propose a new hybrid precoding approach that combines digital and analog precoding to optimize data transmission over multiple antennas. This approach steers signals in specific directions, leading to maximizing sum-rate and suppressing side-lobe interference. When dealing with complex signals, changes in phase are naturally associated with changes in angle, and these variations are inherently correlated. The correlation between the angle and phase is essential for accurately determining the channel characteristics. An important aspect of this approach is that we model the angle and phase as correlated variables following a bivariate Gaussian distribution, and for the first time, we define a joint angle and phase entropy to measure the uncertainty of angle and phase variations in wireless channels. This entropy is crucial to adapt the proposed precoding method with variations. Simulation result validate the accuracy of our analytical findings, demonstrating 18.31% increase in sum-rate and an 11.47% improvement in robustness compared to other state-of-the-art methods.

翻译：混合预编码是充分发挥多用户大规模多输入多输出（MU-MMIMO）系统潜力的关键技术。本文提出了一种结合数字与模拟预编码的新型混合预编码方法，以优化多天线数据传输。该方法通过定向波束赋形，实现了和速率最大化与旁瓣干扰抑制。在处理复信号时，相位变化天然与角度变化相关联，且这些变化具有内在相关性。角度与相位的相关性对于精确刻画信道特性至关重要。本方法的重要创新在于：将角度和相位建模为服从二元高斯分布的相关变量，并首次定义了联合角度-相位熵，用以度量无线信道中角度与相位变化的联合不确定性。该熵值对于使所提预编码方法适应信道变化具有关键作用。仿真结果验证了理论分析的正确性：相较于现有先进方法，本方案使和速率提升18.31%，鲁棒性提高11.47%。