Polar Decomposition Based Hybrid Beamforming Design for mmWave Massive MIMO Systems

This paper considers hybrid beamforming (HBF) for the point-to-point (P2P) millimeter wave (mmWave) massive MIMO systems. The optimal hybrid precoding and combining matrices that maximizes the system capacity can be obtained based on the singular value decomposition (SVD) of the channel matrix. Then, the optimal unconstrained hybrid digital and analog precoders (combiners) are designed according to the polar decomposition of the optimal hybrid precoding (combining) matrix. Considering the actual hardware constraints, we propose a joint transmitter and receiver HBF algorithm based upon polar decomposition. In this algorithm, the hybrid analog constrained precoding and combining matrices can be derived without having to incur an excessive computational complexity of an iterative approach. Simulation results show that the proposed algorithm can approach the performance of optimal unconstrained precoding, and is insensitive to the accuracy of the channel state information (CSI).