Passive communication with ambient noise

TL;DR

This paper proposes a novel passive communication method using ambient noise and tunable metamaterials, enabling data transmission without active signal emission by exploiting wave interactions and statistical properties.

Contribution

It introduces a new passive communication scheme utilizing ambient noise and metamaterials, with a theoretical analysis of wave propagation and encoding/decoding mechanisms.

Findings

Successful encoding of messages via metamaterial modulation.

Decoding achieved through empirical cross spectral density analysis.

Theoretical validation of wave interaction in dispersive media.

Abstract

Motivated by applications to wireless communications, this paper addresses the propagation of waves transmitted by ambient noise sources and interacting with metamaterials. We discuss a generalized Helmholtz-Kirchhoff identity that is valid in dispersive media and we characterize the statistical properties of the empirical cross spectral density of the wave field. We can then introduce and analyze an original communication scheme between two passive arrays that uses only ambient noise illumination. The passive transmitter array does not transmit anything but it is a tunable metamaterial surface that can modulate its dispersive properties and encode a message in the modulation. The passive receiver array made of two receivers that are half-a-wavelength apart from each other can decode the message from the empirical cross spectral density of the wave field.