Movable-Antenna Array Enhanced Downlink NOMA

TL;DR

This paper explores how movable antennas at a base station can be optimized to enhance downlink NOMA performance, significantly increasing sum rates by joint beamforming and antenna positioning.

Contribution

It introduces a novel resource allocation framework for movable antenna arrays in downlink NOMA, jointly optimizing beamforming and antenna positions with a new solution approach.

Findings

MA arrays outperform fixed antennas in sum rate.

Joint optimization yields significant performance gains.

Proposed methods effectively handle non-convex problems.

Abstract

Movable antenna (MA) has gained increasing attention in the field of wireless communications due to its exceptional capability to proactively reconfigure wireless channels via localized antenna movements. In this paper, we investigate the resource allocation design for an MA array-enabled base station serving multiple single-antenna users in a downlink non-orthogonal multiple access (NOMA) system. We aim to maximize the sum rate of all users by jointly optimizing the transmit beamforming and the positions of all MAs at the BS, subject to the constraints of transmit power budget, finite antenna moving region, and the conditions for successive interference cancellation decoding rate. The formulated problem, inherently highly non-convex, is addressed by successive convex approximation (SCA) and alternating optimization methods to obtain a high-quality suboptimal solution. Simulation results unveil that the proposed MA-enhanced downlink NOMA system can significantly improve the sum rate performance compared to both the fixed-position antenna (FPA) system and the traditional orthogonal multiple access (OMA) system.