毫米波大规模MIMO系统中混合预编码设计

Hybrid precoding based on hybrid connection for millimeter-wave massive MIMO system

为了提高混合连接结构毫米波大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)系统的频谱效率,提出一种最大化等效信道增益的混合预编码方案。首先,以原始信道矩阵和模拟预编码矩阵构成等效信道矩阵,并将其分解为各子阵形式,以等效子信道增益之和最大化为目标求取各模拟预编码子矩阵,对其进行块对角组合,从而得到模拟预编码矩阵;然后,运用连续串扰消除的思想逐列求出数字预编码矩阵。仿真结果表明,信噪比为20 dB时,所提方案频谱效率达到最优全数字预编码方案频谱效率的91.7%,在不提高复杂度的情况下,提升了混合连接结构的混合预编码的频谱效率。

In order to improve the spectral efficiency of hybrid precoding in millimeter-wave massive MIMO systems with the hybrid connection structures,a hybrid precoding scheme that maximizes the equivalent channel gain is proposed.Firstly,the equivalent channel matrix is formed by the original channel matrix and the analog precoding matrix,which is decomposed into sub-matrices.Then,each analog precoding sub-matrix is obtained with the goal of maximizing the sum of equivalent sub-channel gains,the entire analog precoding matrix can be acquired by block diagonal combination of them.Finally,the digital precoding matrix can be solved by using the idea of successive interference elimination column by column.The simulation results show that when the signal-to-noise ratio is 20dB,the spectral efficiency of the proposed scheme can reach 91.7%of that of the optimal all digital precoding scheme,the proposed scheme can improve the spectral efficiency of the hybrid precoding of the hybrid connection structure without increasing the complexity.