Fluid Antenna System-Enabled UAV Communications in the Finite Blocklength Regime

2025-11-26

AI Summary

This work addresses reliability modeling and energy efficiency (EE) optimization for fluid antenna system (FAS)-enabled UAV relay networks under finite blocklength constraints. To model spatially and temporally correlated channels, we propose a tractable approach: approximating eigenvalue distributions to capture spatial correlation and incorporating Nakagami-𝑚 fading across diversity branches, enabling derivation of a closed-form block error rate (BLER) expression. Crucially, we are the first to explicitly incorporate both time and energy overheads associated with FAS port selection into the EE maximization framework—departing from conventional idealized assumptions that neglect operational costs. A hierarchical optimization algorithm jointly designs UAV deployment, number of FAS ports, and transmission parameters, yielding scenario-specific optimal strategies for rural and urban environments. Theoretical analysis and simulations demonstrate multi-fold EE gains over baselines in typical deployments, uncovering a fundamental trade-off between port count and EE, and validating the substantial potential of FAS for short-packet communications.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Sampling/Simulation-based Search
• Reasoning under Uncertainty: Stochastic Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

This paper develops a comprehensive framework for the performance analysis of fluid antenna system (FAS)-enabled unmanned aerial vehicle (UAV) relaying networks operating in the finite blocklength regime. Our contribution lies in establishing a rigorous methodology for characterizing system reliability under diverse propagation environments. Closed-form expressions for the block error rate (BLER) are derived by employing a tractable eigenvalue-based approximation of the spatially correlated UAV-to-user link, whose underlying independent diversity components are modeled as Nakagami-$m$ fading. This approach addresses both line-of-sight (LoS) dominant rural and probabilistic non-line-of-sight (NLoS) urban scenarios. Furthermore, a high signal-to-noise ratio (SNR) asymptotic analysis is developed, revealing the fundamental diversity order of the UAV-to-user link. Based on this, we further address the practical issue of energy efficiency. A realistic energy efficiency maximization problem is formulated, which explicitly accounts for the time and energy overhead inherent in the FAS port selection process, a factor often omitted in idealized models. An efficient hierarchical algorithm is then proposed to jointly optimize the key system parameters. Extensive numerical results validate the analysis and illustrate that while FASs can yield substantial power gains, the operational overhead introduces a non-trivial trade-off. This trade-off leads to an optimal number of ports and fundamentally different UAV deployment strategies in rural versus urban environments. This work provides both foundational analysis and practical design guidelines for FAS-enabled UAV communications.

Problem

• Analyzes fluid antenna UAV relay reliability in short-packet communications
• Models block error rate for urban and rural fading environments
• Optimizes energy efficiency considering antenna port selection overhead

Innovation

• Closed-form BLER expressions using eigenvalue-based approximation
• High SNR asymptotic analysis revealing diversity order
• Hierarchical algorithm optimizing energy efficiency with port selection overhead