Hybrid precoding achieves a compromise between the sum rate and hardware complexity of millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems. However, most prior works on multi-user hybrid precoding only consider the full-connected structure. In this paper, a novel multi-user hybrid precoding algorithm is proposed for the sub-connected structure. Based on the improved successive interference cancellation (SIC), the analog precoding matrix optimization problem is decomposed into multiple analog precoding sub-matrix optimization problems. Further, a near-optimal analog precoder is designed through factorizing the precoding sub-matrix for each sub-array. Furthermore, digital precoding is designed according to the block diagonalization (BD) technology. Finally, the water-filling power allocation method is used to further improve the communication quality. The extensive simulation results demonstrate that the sum rate of the proposed algorithm is higher than the existing hybrid precoding methods with the sub-connected structure, and has higher energy efficiency compared with existing approaches. Moreover, the proposed algorithm is closer to the state-of-the-art optimization approach with the full-connected structure. In addition, the simulation results also verify the effectiveness of the proposed hybrid precoding design of the uniform planar array (UPA).

混合预编码实现了毫米波 (mmWave) 大规模多输入多输出 (MIMO) 系统的总速率和硬件复杂性之间的折衷。然而，大多数先前关于多用户混合预编码的工作只考虑全连接结构。本文针对子连接结构提出了一种新的多用户混合预编码算法。基于改进的连续干扰消除(SIC)，将模拟预编码矩阵优化问题分解为多个模拟预编码子矩阵优化问题。此外，通过分解每个子阵列的预编码子矩阵来设计接近最优的模拟预编码器。此外，数字预编码是根据块对角化（BD）技术设计的。最后，采用注水功率分配方式，进一步提高通信质量。大量仿真结果表明，该算法的总和率高于现有的子连接结构混合预编码方法，与现有方法相比具有更高的能量效率。此外，所提出的算法更接近于具有全连接结构的最先进的优化方法。此外，仿真结果还验证了所提出的均匀平面阵列（UPA）混合预编码设计的有效性。并且与现有方法相比具有更高的能源效率。此外，所提出的算法更接近于具有全连接结构的最先进的优化方法。此外，仿真结果还验证了所提出的均匀平面阵列（UPA）混合预编码设计的有效性。并且与现有方法相比具有更高的能源效率。此外，所提出的算法更接近于具有全连接结构的最先进的优化方法。此外，仿真结果还验证了所提出的均匀平面阵列（UPA）混合预编码设计的有效性。