Antenna Positioning and Beamforming Design for Fluid-Antenna Enabled Multi-user Downlink Communications

TL;DR

This paper proposes a joint optimization of fluid antenna positions and beamforming in a MISO downlink system to minimize power consumption, demonstrating improved performance over fixed antennas.

Contribution

It introduces a novel joint optimization framework for fluid antenna positioning and beamforming, employing an AO algorithm with SCA for non-convex problems.

Findings

Fluid antennas outperform fixed-position antennas in power efficiency.

The proposed optimization reduces total transmit power.

Numerical results validate the effectiveness of the joint design.

Abstract

This paper investigates a multiple input single output (MISO) downlink communication system in which users are equipped with fluid antennas (FAs). First, we adopt a field-response based channel model to characterize the downlink channel with respect to FAs' positions. Then, we aim to minimize the total transmit power by jointly optimizing the FAs' positions and beamforming matrix. To solve the resulting non-convex problem, we employ an alternating optimization (AO) algorithm based on penalty method and successive convex approximation (SCA) to obtain a sub-optimal solution. Numerical results demonstrate that the FA-assisted communication system performs better than conventional fixed position antennas system.