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.

翻译：流体天线系统能够利用无线信道中的空间自由度。本文为在频率选择性环境中利用空间自由度，研究了一种采用正交频分复用技术的空中计算系统，其中接入点配备二维流体天线以提升性能。我们通过将原问题转化为发射预编码器优化问题，以及天线位置与接收合并器联合优化问题，以最小化计算均方误差。后者采用主化最小化方法与序列优化相结合的策略求解。数值结果表明，所提方案相比固定位置天线方案实现了均方误差的降低。