OFDM Enabled Over-the-Air Computation Systems with Two-Dimensional Fluid Antennas

TL;DR

This paper proposes an OFDM-based over-the-air computation system using a two-dimensional fluid antenna system at the access point, optimizing antenna positions and transmit/receive strategies to reduce mean square error in frequency-selective channels.

Contribution

It introduces a novel integration of fluid antennas with OFDM for over-the-air computation, optimizing antenna placement and signal processing to improve performance.

Findings

Achieves lower MSE compared to fixed antenna schemes.

Optimizes antenna positions and transmit/receive strategies.

Demonstrates effectiveness in frequency-selective environments.

Abstract

Fluid antenna system (FAS) is able to exploit spatial degrees of freedom (DoFs) in wireless channels. In this letter, to exploit spatial DoFs in frequency-selective environments, we investigate an orthogonal frequency division multiplexing enabled over-the-air computation system, where the access point is equipped with a two-dimensional FAS to enhance performance. We solve the computation mean square error (MSE) minimization problem by transforming the original problem into transmit precoders optimization problem and antenna positions optimization along with receive combiners optimization problem. The latter is solved via a majorization-minimization approach combined with sequential optimization. Numerical results confirm that the proposed scheme achieves MSE reduction over the scheme with fixed position antennas.