Positioning via Digital-Twin-Aided Channel Charting with Large-Scale CSI Features

TL;DR

This paper introduces a digital twin-assisted channel charting method that accurately estimates true spatial positions from large-scale CSI features, improving positioning accuracy without labeled data.

Contribution

A novel framework integrating digital twins with channel charting to produce true spatial coordinates from CSI data, reducing error and enhancing robustness.

Findings

Reduces relative mean distance error by 29% compared to state-of-the-art methods.

Demonstrates robustness to digital twin modeling mismatches.

Effective in simulated indoor scenarios.

Abstract

Channel charting (CC) is a self-supervised positioning technique whose main limitation is that the estimated positions lie in an arbitrary coordinate system that is not aligned with true spatial coordinates. In this work, we propose a novel method to produce CC locations in true spatial coordinates with the aid of a digital twin (DT). Our main contribution is a new framework that (i) extracts large-scale channel-state information (CSI) features from estimated CSI and the DT and (ii) matches these features with a cosine-similarity loss function. The DT-aided loss function is then combined with a conventional CC loss to learn a positioning function that provides true spatial coordinates without relying on labeled data. Our results for a simulated indoor scenario demonstrate that the proposed framework reduces the relative mean distance error by 29% compared to the state of the art. We also show that the proposed approach is robust to DT modeling mismatches and a distribution shift in the testing data.