Hybrid Codebook Design for Localization Using Electromagnetically Reconfigurable Fluid Antenna System

Fuente: arXiv
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Autori principali: Fadakar, Alireza, Zhang, Yuchen, Chen, Hui, Keskin, Musa Furkan, Wymeersch, Henk, Molisch, Andreas F.
Natura: Preprint
Pubblicazione: 2025
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author Fadakar, Alireza
Zhang, Yuchen
Chen, Hui
Keskin, Musa Furkan
Wymeersch, Henk
Molisch, Andreas F.
author_facet Fadakar, Alireza
Zhang, Yuchen
Chen, Hui
Keskin, Musa Furkan
Wymeersch, Henk
Molisch, Andreas F.
contents Electromagnetically reconfigurable fluid antenna systems (ER-FAS) introduce additional degrees of freedom in the electromagnetic (EM) domain by dynamically steering per-antenna radiation patterns, thereby enhancing power efficiency in wireless links. Unlike prior works on spatially reconfigurable FAS, which adjust element positions, ER-FAS provides direct control over each element's EM characteristics to realize on-demand beam-pattern shaping. While existing studies have exploited ER-FAS to boost spectral efficiency, this paper explores its application for downlink localization. We consider a multiple-input single-output (MISO) system in which a multi-antenna ER-FAS at the base station serves a single-antenna user equipment (UE). We consider two reconfigurability paradigms: (i) a synthesis model where each antenna generates desired beampatterns from a finite set of EM basis functions, and (ii) a finite-state selection model in which each antenna selects a pattern from a predefined set of patterns. For both paradigms, we formulate the joint baseband (BB) and EM precoder design to minimize the UE position error bound. In the synthesis case we derive low-dimensional closed-form expressions for both the BB and EM precoders. For the finite-state model we obtain closed-form BB structures and propose a low-complexity block-coordinate-descent algorithm for EM pattern selection. Analytical bounds and extensive simulations show that the proposed hybrid designs for ER-FAS substantially improve UE positioning accuracy over traditional non-reconfigurable arrays.
format Preprint
id arxiv_https___arxiv_org_abs_2508_21351
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid Codebook Design for Localization Using Electromagnetically Reconfigurable Fluid Antenna System
Fadakar, Alireza
Zhang, Yuchen
Chen, Hui
Keskin, Musa Furkan
Wymeersch, Henk
Molisch, Andreas F.
Signal Processing
Electromagnetically reconfigurable fluid antenna systems (ER-FAS) introduce additional degrees of freedom in the electromagnetic (EM) domain by dynamically steering per-antenna radiation patterns, thereby enhancing power efficiency in wireless links. Unlike prior works on spatially reconfigurable FAS, which adjust element positions, ER-FAS provides direct control over each element's EM characteristics to realize on-demand beam-pattern shaping. While existing studies have exploited ER-FAS to boost spectral efficiency, this paper explores its application for downlink localization. We consider a multiple-input single-output (MISO) system in which a multi-antenna ER-FAS at the base station serves a single-antenna user equipment (UE). We consider two reconfigurability paradigms: (i) a synthesis model where each antenna generates desired beampatterns from a finite set of EM basis functions, and (ii) a finite-state selection model in which each antenna selects a pattern from a predefined set of patterns. For both paradigms, we formulate the joint baseband (BB) and EM precoder design to minimize the UE position error bound. In the synthesis case we derive low-dimensional closed-form expressions for both the BB and EM precoders. For the finite-state model we obtain closed-form BB structures and propose a low-complexity block-coordinate-descent algorithm for EM pattern selection. Analytical bounds and extensive simulations show that the proposed hybrid designs for ER-FAS substantially improve UE positioning accuracy over traditional non-reconfigurable arrays.
title Hybrid Codebook Design for Localization Using Electromagnetically Reconfigurable Fluid Antenna System
topic Signal Processing
url https://arxiv.org/abs/2508.21351