Compressed Sensing-Driven Near-Field Localization Exploiting Array of Subarrays

TL;DR

SHARE is a two-stage sparse recovery algorithm that enhances near-field localization accuracy and robustness using subarray architectures, outperforming traditional methods and rivaling fully-digital approaches.

Contribution

The paper introduces SHARE, a hierarchical sparse recovery method that effectively resolves grating lobes and achieves high-resolution localization with reduced hardware complexity.

Findings

SHARE outperforms conventional sparse recovery methods like OMP in accuracy and robustness.

SHARE achieves localization accuracy comparable to fully-digital 2D-MUSIC.

The hierarchical approach reduces computational complexity compared to exhaustive grid searches.

Abstract

Near-field localization for ISAC requires large-aperture arrays, making fully-digital implementations prohibitively complex and costly. While sparse subarray architectures can reduce cost, they introduce severe estimation ambiguity from grating lobes. To address both issues, we propose SHARE (Sparse Hierarchical Angle-Range Estimation), a novel two-stage sparse recovery algorithm. SHARE operates in two stages. It first performs coarse, unambiguous angle estimation using individual subarrays to resolve the grating lobe ambiguity. It then leverages the full sparse aperture to perform a localized joint angle-range search. This hierarchical approach avoids an exhaustive and computationally intensive two-dimensional grid search while preserving the high resolution of the large aperture. Simulation results show that SHARE significantly outperforms conventional one-shot sparse recovery methods, such as Orthogonal Matching Pursuit (OMP), in both localization accuracy and robustness. Furthermore, we show that SHARE's overall localization accuracy is comparable to or even surpasses that of the fully-digital 2D-MUSIC algorithm, despite MUSIC having access to the complete, uncompressed data from every antenna element. SHARE therefore provides a practical path for high-resolution near-field ISAC systems.