一种抑制残余硬件损伤影响的毫米波大规模MIMO混合预编码方案

A Hybrid Precoding Scheme for Millimeter Wave Massive MIMO System with Residual Hardware Impairments

在假设通信收发机具有理想硬件特性的前提下,毫米波大规模多输入多输出(MIMO)系统的混合预编码问题已经获得了广泛的研究。然而,由通信收发机硬件非理想特性导致的残余硬件损伤在毫米波大规模MIMO系统中难以避免,并且会严重影响混合预编码的性能。针对这一问题,该文建立了在收发机残余硬件损伤影响下的毫米波大规模MIMO混合预编码模型,提出一种基于流形优化的混合预编码方案。首先根据收发信号之间的修正均方误差建立优化目标,进而推导出数字预编码矩阵与数字组合矩阵的闭合表达式,然后基于黎曼流形处理恒模约束问题获得模拟预编码矩阵与模拟组合矩阵,最后进行收发机交替迭代获得混合预编码的优化结果。仿真结果表明,该方案有效抑制了残余硬件损伤对毫米波大规模MIMO系统的不利影响,显著提升了系统的性能。

Based on the assumption of perfect transceiver hardware,the hybrid precoding of millimeter wave massive Multiple-Input Multiple-Output(MIMO)system has been extensively studied.However,the residual hardware impairments caused by non-ideal characteristics of transceivers are unavoidable in millimeter wave massive MIMO system,which lead to hybrid precoding performance degradation seriously.To address this problem,the hybrid precoding model which considers the impact of residual hardware impairments is built for millimeter wave massive MIMO system and a hybrid precoding scheme based on manifold optimization is proposed in this paper.Firstly,the optimization objective is designed with the modified mean square error.Then the closed-form expressions of the digital precoding and digital combining matrix are derived and the optimal solutions of the analog precoding matrix and the combining matrix are obtained by dealing with the constant modulus constraint on the Riemannian manifold.Finally,the joint hybrid precoding and combining design are achieved by iteratively and alternatively optimizing the hybrid precoding and the hybrid combining matrix.The simulation results show that the proposed scheme suppresses effectively the impact of residual hardware impairments on the millimeter-wave massive MIMO system,and improves significantly the system performance.