Cramer-Rao Bound for Angle of Arrival Estimates in True-Time-Delay Systems

TL;DR

This paper derives the Cramer-Rao Bound for angle of arrival estimation in true-time-delay systems, providing theoretical insights and evaluating practical estimators for improved joint communication and sensing.

Contribution

It introduces the CRB for AoA in TTD systems and analyzes properties, offering a theoretical foundation for angle estimation in advanced beamforming applications.

Findings

CRB derived for AoA in TTD systems

Properties of Fisher information analyzed

Numerical evaluation of estimators conducted

Abstract

In the context of joint communication and sensing JC&S, the challenge of obtaining accurate parameter estimates is of interest. Parameter estimates, such as the AoA can be utilized for solving the initial access problem, interference mitigation, localization of users or monitoring of the environment and synchronization of MIMO systems. Recently, TTD systems have gained attention for fast beam training during initial access and mitigation of beam squinting. This work derives the CRB for angle estimates in typical TTD systems. Properties of the CRB and the Fisher information are investigated and numerically evaluated. Finally, methods for angle estimation such as ML and established estimators are utilized to solve the angle estimation problem using a uniform linear array.