# Hybrid MMSE Beamforming for Multiuser Millimeter Wave Communication Systems

## TL;DR

This paper proposes a hybrid MMSE beamforming approach for multiuser mmWave systems, optimizing analog and digital components iteratively to achieve near-optimal performance with efficient computation.

## Contribution

It introduces a novel hybrid beamforming design based on MMSE criterion with closed-form solutions and an alternating minimization algorithm.

## Key findings

- Fast convergence of the proposed scheme
- Performance close to fully digital beamforming
- Efficient analog and digital beamformer optimization

## Abstract

This letter investigates the hybrid analog and digital beamforming (HBF) design for multiuser millimeter wave (mmWave) communication systems based on the minimum mean square error (MMSE) criterion. Using the alternating minimization method, the hybrid precoder of the base station (BS) and the hybrid combiners of the users are alternatively optimized. It is shown that both the optimized digital precoder of the BS and the digital combiners of the users have closed-form expressions, and their corresponding analog ones can be efficiently obtained via generalized eigen-decomposition. Simulation results show that the proposed MMSE HBF scheme has fast convergence and performs close to the fully digital beamforming.