FAS-ARIS: Turning Multipath Challenges Into Localization Opportunities

Fuente: arXiv
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Main Authors: Chen, Hua, Gong, Tao, Wu, Tuo, Elkashlan, Maged, Liu, Baiyang, Chae, Chan-Byoung, Tong, Kin-Fai, Wong, Kai-Kit
Format: Preprint
Published: 2025
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author Chen, Hua
Gong, Tao
Wu, Tuo
Elkashlan, Maged
Liu, Baiyang
Chae, Chan-Byoung
Tong, Kin-Fai
Wong, Kai-Kit
author_facet Chen, Hua
Gong, Tao
Wu, Tuo
Elkashlan, Maged
Liu, Baiyang
Chae, Chan-Byoung
Tong, Kin-Fai
Wong, Kai-Kit
contents Traditional single-input single-output (SISO) systems face fundamental limitations in achieving accurate three-dimensional (3D) localization due to limited spatial degrees of freedom (DoF) and the adverse impact of multipath propagation. This paper proposes a novel fluid antenna system (FAS)-active reconfigurable intelligent surface (ARIS) framework that transforms multipath effects from a hindrance into a resource for enhanced localization. By synergistically combining the signal amplification capabilities of ARIS with the spatial diversity enabled by FAS, the proposed system achieves robust 3D user equipment (UE) positioning -- without relying on auxiliary information such as time-of-arrival (ToA) or frequency diversity. The system exploits both line-of-sight (LoS) and non-line-of-sight (NLoS) components through a tailored signal decoupling strategy. We design novel UE pilot sequences and ARIS phase configurations to effectively separate LoS and NLoS channels, enabling independent parameter estimation. A multi-stage estimation algorithm is then applied: the multiple signal classification (MUSIC) algorithm estimates angle-of-arrival (AoA) from the direct path, while maximum likelihood estimation with interior-point refinement recovers cascaded channel parameters from the reflected path. Finally, geometric triangulation using least-squares estimation determines the UE's 3D position based on the extracted AoA information. Comprehensive performance analysis, including the derivation of Cramér-Rao bounds for both channel and position estimation, establishes theoretical benchmarks. Simulation results confirm that the proposed FAS-ARIS framework achieves near-optimal localization accuracy while maintaining robustness in rich multipath environments -- effectively turning conventional localization challenges into advantages.
format Preprint
id arxiv_https___arxiv_org_abs_2509_12348
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle FAS-ARIS: Turning Multipath Challenges Into Localization Opportunities
Chen, Hua
Gong, Tao
Wu, Tuo
Elkashlan, Maged
Liu, Baiyang
Chae, Chan-Byoung
Tong, Kin-Fai
Wong, Kai-Kit
Signal Processing
Traditional single-input single-output (SISO) systems face fundamental limitations in achieving accurate three-dimensional (3D) localization due to limited spatial degrees of freedom (DoF) and the adverse impact of multipath propagation. This paper proposes a novel fluid antenna system (FAS)-active reconfigurable intelligent surface (ARIS) framework that transforms multipath effects from a hindrance into a resource for enhanced localization. By synergistically combining the signal amplification capabilities of ARIS with the spatial diversity enabled by FAS, the proposed system achieves robust 3D user equipment (UE) positioning -- without relying on auxiliary information such as time-of-arrival (ToA) or frequency diversity. The system exploits both line-of-sight (LoS) and non-line-of-sight (NLoS) components through a tailored signal decoupling strategy. We design novel UE pilot sequences and ARIS phase configurations to effectively separate LoS and NLoS channels, enabling independent parameter estimation. A multi-stage estimation algorithm is then applied: the multiple signal classification (MUSIC) algorithm estimates angle-of-arrival (AoA) from the direct path, while maximum likelihood estimation with interior-point refinement recovers cascaded channel parameters from the reflected path. Finally, geometric triangulation using least-squares estimation determines the UE's 3D position based on the extracted AoA information. Comprehensive performance analysis, including the derivation of Cramér-Rao bounds for both channel and position estimation, establishes theoretical benchmarks. Simulation results confirm that the proposed FAS-ARIS framework achieves near-optimal localization accuracy while maintaining robustness in rich multipath environments -- effectively turning conventional localization challenges into advantages.
title FAS-ARIS: Turning Multipath Challenges Into Localization Opportunities
topic Signal Processing
url https://arxiv.org/abs/2509.12348