Leakage-based hybrid beamforming design for downlink multiuser mmWave MIMO systems

This paper considers hybrid beamforming (HBF) for a downlink multiuser millimeter-wave (mmWave) multiple input multiple output (MIMO) system. For this system, we propose a signal-to-leakage-and-noise (SLNR) based HBF algorithm. In this algorithm, we first consider jointly designing the analog precoder and combiner to maximize the RF chain gain between the BS and each user. Then, the digital precoder is designed with the aim at maximizing SLNR, when the analog precoder and combiner are fixed. This optimization problem can be further equivalent to generalized eigenvalue problem, and the optimal digital precoding vector for each stream can be obtained one by one by using generalized Rayleigh-Ritz quotient. Simulation results demonstrate that the performance of the proposed algorithm outperforms the existing algorithms, and are extremely close to the hypothetical single-user (no interference) case.