Distributed MIMO Positioning: Fundamental Limit Analysis and User Tracking Framework Design

Fuente: arXiv
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Main Authors: Xu, Yingjie, Cai, Xuesong, Al-Ameri, Ali, Willhammar, Sara, Tufvesson, Fredrik
Format: Preprint
Published: 2025
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author Xu, Yingjie
Cai, Xuesong
Al-Ameri, Ali
Willhammar, Sara
Tufvesson, Fredrik
author_facet Xu, Yingjie
Cai, Xuesong
Al-Ameri, Ali
Willhammar, Sara
Tufvesson, Fredrik
contents This paper presents a comprehensive study on the 3D positioning capabilities in distributed multiple-input multiple-output (MIMO) systems. Unlike previous studies that mainly rely on idealized isotropic antenna models, we adopt a polarimetric model that takes advantage of effective aperture distribution functions to characterize realistic antenna patterns, placements, and polarization effects. Based on this model, we analyze the fundamental limits of UE positioning using the Fisher information matrix (FIM) and the position error bound (PEB). The FIM is shown to be expressed as a weighted sum of the information contributions from individual access point (AP)-UE pairs, with each contribution interpreted geometrically across distance, azimuth, and elevation dimensions. The impact of the UE tilt and the spatial distribution of APs on the PEBs is further analyzed. As a further advancement, we propose a complete positioning framework from a UE tracking perspective. By integrating a global probability hypothesis density filter and a PEB-aware AP management strategy, the framework enables accurate tracking while optimizing AP scheduling. Finally, we present a distributed MIMO channel measurement campaign to validate the proposed framework. The results demonstrate a centimeter-level tracking accuracy. In addition, the PEB-aware AP management strategy is shown to maintain robust tracking performance while significantly reducing the number of concurrently active APs, thus lowering the overall system overhead.
format Preprint
id arxiv_https___arxiv_org_abs_2511_06440
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Distributed MIMO Positioning: Fundamental Limit Analysis and User Tracking Framework Design
Xu, Yingjie
Cai, Xuesong
Al-Ameri, Ali
Willhammar, Sara
Tufvesson, Fredrik
Signal Processing
This paper presents a comprehensive study on the 3D positioning capabilities in distributed multiple-input multiple-output (MIMO) systems. Unlike previous studies that mainly rely on idealized isotropic antenna models, we adopt a polarimetric model that takes advantage of effective aperture distribution functions to characterize realistic antenna patterns, placements, and polarization effects. Based on this model, we analyze the fundamental limits of UE positioning using the Fisher information matrix (FIM) and the position error bound (PEB). The FIM is shown to be expressed as a weighted sum of the information contributions from individual access point (AP)-UE pairs, with each contribution interpreted geometrically across distance, azimuth, and elevation dimensions. The impact of the UE tilt and the spatial distribution of APs on the PEBs is further analyzed. As a further advancement, we propose a complete positioning framework from a UE tracking perspective. By integrating a global probability hypothesis density filter and a PEB-aware AP management strategy, the framework enables accurate tracking while optimizing AP scheduling. Finally, we present a distributed MIMO channel measurement campaign to validate the proposed framework. The results demonstrate a centimeter-level tracking accuracy. In addition, the PEB-aware AP management strategy is shown to maintain robust tracking performance while significantly reducing the number of concurrently active APs, thus lowering the overall system overhead.
title Distributed MIMO Positioning: Fundamental Limit Analysis and User Tracking Framework Design
topic Signal Processing
url https://arxiv.org/abs/2511.06440