# A Fisher Information Analysis of Joint Localization and Synchronization in Near Field

## TL;DR

This paper analyzes the impact of near-field effects on joint localization and synchronization in 5G systems, highlighting the importance of wavefront curvature and proposing a simple algorithm for coarse estimation.

## Contribution

It provides a Fisher information-based comparison of near-field and far-field localization performance and introduces a straightforward method for initial user position and clock bias estimation.

## Key findings

- Near-field effects significantly affect localization accuracy.
- Wavefront curvature must be considered for large arrays.
- A simple algorithm offers effective coarse estimates.

## Abstract

In 5G communication, arrays are used for both positioning and communication. As the arrays become larger, the far-field assumption is increasingly being violated and curvature of the wavefront should be taken into account. We explicitly contrast near-field and far-field uplink localization performance in the presence of a clock bias from a Fisher information perspective and show how a simple algorithm can provide a coarse estimate of a user's location and clock bias.