By recognizing the tremendous flexibility of the emerging fluid antenna system (FAS), which allows dynamic reconfigurability of the location of the antenna within a given space, this paper investigates the performance of a single-antenna FAS over spatially correlated Nakagami-$m$ fading channels. Specifically, simple and highly accurate closed-form approximations for the cumulative density function of the FAS channel and the outage probability of the proposed system are obtained by employing a novel asymptotic matching method, which is an improved version of the well-known moment matching. With this method, the outage probability can be computed {simply} without incurring complex multi-fold integrals, thus requiring negligible computational effort. Finally, the accuracy of the proposed approximations is validated, and it is shown that the FAS can meet or even exceed the performance attained by the conventional maximal ratio combining (MRC) technique.

翻译：本文通过认识新兴流体天线系统(FAS)的巨大灵活性——该技术可在给定空间内动态重构天线位置——研究了单天线FAS在空间相关Nakagami-$m$衰落信道下的性能。具体而言，通过采用一种新颖的渐近匹配方法（即著名矩匹配法的改进版本），获得了FAS信道累积密度函数及所提系统中断概率的简便且高精度闭式近似。利用该方法，无需进行复杂的多重积分即可简便计算中断概率，从而将计算开销降至可忽略水平。最后，验证了所提近似的准确性，并表明FAS能够达到甚至超越传统最大比合并(MRC)技术的性能表现。