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arXiv · 2512.18970

FAS-RIS for V2X: Unlocking Realistic Performance Analysis with Finite Elements

Tuo Wu·Xiazhi Lai·Maged Elkashlan·Naofal Al-Dhahir·Matthew C. Valenti·Fumiyuki Adachi
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Abstract

The synergy of fluid antenna systems (FAS) and reconfigurable intelligent surfaces (RIS) is poised to unlock robust Vehicle-to-Everything (V2X) communications. However, a critical gap persists between theoretical predictions and real-world performance. Existing analyses predominantly rely on the Central Limit Theorem (CLT), an assumption valid only for a large number of RIS elements, which fails to represent practical, finite-sized deployments constrained by cost and urban infrastructure. This paper bridges this gap by presenting a novel framework that unlocks a realistic performance analysis for FAS-RIS systems with finite elements. Leveraging a Gamma distribution approximation, we derive a new, tractable closed-form expression for the outage probability. Numerical results validate our approach, demonstrating that it offers a significantly more accurate performance characterization than conventional CLT-based methods, particularly in the practical regime of small-scale RIS. This work provides a crucial foundation for the design and deployment of reliable FAS-RIS-aided vehicular networks.

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Tuo Wu, Xiazhi Lai, Maged Elkashlan, Naofal Al-Dhahir, Matthew C. Valenti, Fumiyuki Adachi. 2025-12-22. FAS-RIS for V2X: Unlocking Realistic Performance Analysis with Finite Elements. https://arxiv.org/abs/2512.18970

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