A general hybrid precoding method for mmWave massive MIMO systems

Recently, hybrid precoding architectures have been proposed for the purpose of practical implementation of massive Multiple-Input Multiple-Output (MIMO) systems in the Fifth Generation (5G) networks. In this paper, a general precoding method is investigated for Millimeter Wave (mmWave) multi-user systems, which is composed of the designs in analog Radio Frequency (RF) and digital baseband matrices. In the general hybrid architecture, the analog part is constituted of independent analog sub-arrays with full connection inside. The analog precoding matrix is considered by maximizing Signal-to-Leakage-plus-Noise Ratio (SLNR) with only the long-term statistics of user groups. Due to the constant module constraint of RF chains, a supplemental matrix is introduced to reduce the performance loss. The digital precoding matrix performs Regularized Zero-Forcing (RZF) with the reduced amount of effective channels. Finally, simulation results demonstrate the performance improvement of the proposed precoding method. Meanwhile, trade-off between the performance and the complexity is handled well by the proposed method.