Hybrid Beamforming for Subarray-Level Movable Antenna Enhanced MU-MIMO Communications

TL;DR

This paper proposes a hybrid beamforming scheme for MU-MIMO systems with movable subarray antennas, optimizing both beamforming and antenna positions to significantly improve spectral efficiency.

Contribution

It introduces a joint optimization framework for hybrid beamforming and subarray positions in movable antenna MU-MIMO systems, outperforming fixed-position schemes.

Findings

The SIC-MA method outperforms the SIC-FPA benchmark in spectral efficiency.

Joint optimization of beamforming and antenna positions enhances system performance.

Simulation results confirm the effectiveness of the proposed approach.

Abstract

This study investigates subarray-level movable antenna (MA) architecture for multi-user MIMO (MU-MIMO) systems. Unlike conventional systems with fixed-position antennas (FPAs), the proposed scheme harnesses the additional positional degrees of freedom (DoFs) of movable subarrays to enhance spatial multiplexing capabilities for both multi-user and multi-stream communications. Our objective is to maximize the overall system spectral efficiency by jointly optimizing the hybrid beamforming design and the positions of all subarrays. To tackle this challenging non-convex optimization problem, we first adopt a block diagonalization (BD) based digital precoder to effectively eliminate multi-user interference. Subsequently, the joint optimization of the analog beamformer and the subarray positions is efficiently solved using a sequential interference cancellation (SIC)-based algorithm. Simulation results demonstrate that the proposed SIC-MA method significantly outperforms the benchmark SIC-FPA scheme where subarrays are fixed.