Asymptotic Performance Analysis of Fluid Antenna Systems: An Extreme Value Theory Perspective

2025-11-21

AI Summary

This work investigates the asymptotic performance limits of fluid antenna systems (FAS) with a large number of antenna ports. Conventional analytical approaches fail to characterize the scaling laws of reliability and capacity in high-dimensional FAS. To address this, we introduce extreme value theory—specifically, the Gumbel distribution—for the first time to model FAS performance. We establish that the outage probability (OP) decays exponentially with the number of ports (N) as (sim e^{-a N}), while the ergodic capacity (EC) grows double-logarithmically as (sim log log N). Tight analytical upper and lower bounds on both OP and EC are derived, and we rigorously prove that spatial correlation significantly degrades asymptotic performance. All theoretical findings are corroborated by extensive numerical simulations. This study provides a fundamental theoretical benchmark and critical design guidelines for the large-scale deployment of FAS.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Other Foundations of Multi Agent Systems
• Reasoning under Uncertainty: Stochastic Optimization

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Social Networks and Social Media: Social media analysis through the lenses of networks

Abstract

Fluid antenna systems (FAS) allow dynamic reconfiguration to achieve superior diversity gains and reliability. To quantify the performance scaling of FAS with a large number of antenna ports, this paper leverages extreme value theory (EVT) to conduct an asymptotic analysis of the outage probability (OP) and ergodic capacity (EC). The analysis reveals that the OP decays approximately exponentially with the number of antenna ports. Moreover, we establish upper and lower bounds for the asymptotic EC, uncovering its double-logarithmic scaling law. Furthermore, we re-substantiate these scaling laws by exploiting the fact that the mode of the Gumbel distribution scales logarithmically. Besides, we theoretically prove that spatial correlation among antenna ports degrades both OP and EC. All analytical findings are conclusively validated by numerical results.

Problem

• Analyzing asymptotic performance of fluid antenna systems
• Quantifying outage probability and ergodic capacity scaling
• Investigating spatial correlation impact on system performance

Innovation

• Fluid antenna systems enable dynamic reconfiguration for diversity
• Extreme value theory analyzes outage probability and capacity
• Outage probability decays exponentially with antenna ports