Cramer--Rao Bounds for Magneto-Inductive Integrated Sensing and Communications

TL;DR

This paper derives a closed-form Cramér-Rao bound for joint range and conductivity estimation in magnetic induction-based sensing and communication, showing that conductivity sensing minimally impacts ranging accuracy.

Contribution

It introduces a novel CRB analysis for MI-based ISAC systems, quantifying the estimation limits and the impact of conductivity sensing on ranging performance.

Findings

Joint estimation penalty converges to 3 dB in near-field

Conductivity sensing adds at most a factor-of-two loss in precision

Monte Carlo simulations confirm CRB achievability

Abstract

Magnetic induction (MI) enables communication in RF-denied environments (underground, underwater, in-body), where the medium conductivity imprints a deterministic signature on the channel. This letter derives a closed-form Cram\'{e}r--Rao bound (CRB) for the joint estimation of range and medium conductivity from MI pilot observations in an integrated sensing and communication (ISAC) framework. The Fisher information matrix reveals that the joint estimation penalty converges to 3\,dB in the near-field regime, meaning conductivity sensing adds at most a factor-of-two loss in ranging precision. Monte Carlo maximum-likelihood simulations confirm that the CRB is achievable under practical operating conditions.