Massive connectivity with ultra-low latency and high reliability necessitates fundamental advances in future communication networks operating under finite-blocklength (FBL) transmission. Fluid antenna systems (FAS) have emerged as a promising enabler, offering superior spectrum and energy efficiency in short-packet/FBL scenarios. In this work, by leveraging the simplicity and accuracy of block-correlation channel modeling, we rigorously bound the performance limits of FBL-FAS from a statistical perspective, focusing on two key performance metrics: block error rate (BLER) and outage probability (OP). Furthermore, we introduce a novel complex-integral simplification method based on Gauss-Laguerre quadrature, which achieves higher approximation accuracy compared to existing Taylor-expansion-based approaches. Numerical results validate the robustness of the proposed analysis and clearly demonstrate the superiority of FBL-FAS over conventional multiple-antenna systems with fixed antenna placement.

翻译：超低时延与高可靠性的大规模连接需求，对在有限块长传输下运行的未来通信网络提出了根本性改进要求。流体天线系统作为一种前景广阔的技术赋能方案，在短包/有限块长场景中展现出卓越的频谱与能量效率。本研究通过采用简洁精确的块相关信道建模方法，从统计视角严格推导了有限块长流体天线系统的性能边界，重点关注两个关键性能指标：块错误率与中断概率。此外，我们提出了一种基于高斯-拉盖尔积分的新型复积分简化方法，相较于现有基于泰勒展开的近似方法，该方法实现了更高的逼近精度。数值仿真结果验证了所提分析框架的鲁棒性，并清晰证明了有限块长流体天线系统相对于传统固定天线布局多天线系统的优越性。