Information transfer through disordered media by diffuse waves

TL;DR

This paper analyzes how diffuse waves in disordered media can transfer information, showing that the information capacity scales with the number of transmitters and depends on wave correlations due to the medium's mesoscopic properties.

Contribution

It provides explicit analytic expressions for the information capacity of diffuse wave channels, linking mesoscopic correlations to channel capacity in disordered media.

Findings

Average capacity scales linearly with the number of transmitters

Explicit formulas for capacity per transmitter in large system limits

Capacity depends on wave coherence and medium's mesoscopic correlations

Abstract

We consider the information content h of a scalar multiple-scattered, diffuse wave field $\psi(\vec{r})$ and the information capacity C of a communication channel that employs diffuse waves to transfer the information through a disordered medium. Both h and C are shown to be directly related to the mesoscopic correlations between the values of $\psi(\vec{r})$ at different positions $\vec{r}$ in space, arising due to the coherent nature of the wave. For the particular case of a communication channel between two identical linear arrays of $n \gg 1$ equally-spaced transmitters/receivers (receiver spacing a), we show that the average capacity $<C> \propto n$ and obtain explicit analytic expressions for $<C>/n$ in the limit of $n \to \infty$ and $k \ell \to \infty$, where $k= 2\pi/ \lambda$, $\lambda$ is the wavelength, and $\ell$ is the mean free path. Modification of the above results in the case of finite but large n and $k \ell$ is discussed as well.