Ziv-Zakai Bound for Near-Field Localization and Sensing

TL;DR

This paper analyzes the Ziv-Zakai Bound for near-field localization with large antenna arrays, providing a more accurate estimation accuracy characterization than traditional bounds, especially in challenging conditions.

Contribution

It introduces the application of the Ziv-Zakai Bound to near-field localization, accounting for spherical wavefronts and array geometry, which is novel compared to prior work using CRB.

Findings

ZZB offers tighter bounds than CRB in low SNR regimes

Estimates depend critically on array geometry and wavelength

Fundamental limits of near-field sensing are characterized

Abstract

The increasing carrier frequencies and growing physical dimensions of antenna arrays in modern wireless systems are driving renewed interest in localization and sensing under near-field conditions. In this paper, we analyze the Ziv-Zakai Bound (ZZB) for near-field localization and sensing operated with large antenna arrays, which offers a tighter characterization of estimation accuracy compared to traditional bounds such as the Cram\'er-Rao Bound (CRB), especially in low signal-to-noise ratio or threshold regions. Leveraging spherical wavefront and array geometry in the signal model, we evaluate the ZZB for distance and angle estimation, investigating the dependence of the accuracy on key signal and system parameters such as array geometry, wavelength, and target position. Our analysis highlights the transition behavior of the ZZB and underscores the fundamental limitations and opportunities for accurate near-field sensing.