In conventional multiple-input multiple-output (MIMO) communication systems, the positions of antennas are fixed. To take full advantage of spatial degrees of freedom, a new technology called fluid antenna (FA) is proposed to obtain higher achievable rate and diversity gain. Most existing works on FA exploit instantaneous channel state information (CSI). However, in FA-assisted systems, it is difficult to obtain instantaneous CSI since changes in the antenna position will lead to channel variation. In this letter, we investigate a FA-assisted MIMO system using relatively slow-varying statistical CSI. Specifically, in the criterion of rate maximization, we propose an algorithmic framework for transmit precoding and transmit/receive FAs position designs with statistical CSI. Simulation results show that our proposed algorithm in FA-assisted systems significantly outperforms baselines in terms of rate performance.

翻译：在传统的多输入多输出（MIMO）通信系统中，天线位置是固定的。为了充分利用空间自由度，一种名为流体天线（FA）的新技术被提出，以获得更高的可达速率和分集增益。现有的大多数关于FA的研究利用了瞬时信道状态信息（CSI）。然而，在FA辅助系统中，由于天线位置的变化会导致信道变化，因此获取瞬时CSI较为困难。本文研究了一种使用相对慢变的统计CSI的FA辅助MIMO系统。具体而言，在速率最大化的准则下，我们提出了一种基于统计CSI的发射预编码与发射/接收FA位置联合设计的算法框架。仿真结果表明，我们提出的FA辅助系统算法在速率性能上显著优于基线方法。