Electromagnetic channel capacity for practical purposes

TL;DR

This paper derives practical upper bounds on the capacity of electromagnetic channels with thermal noise, relevant for real-world radio and optical communications, especially in high-noise, low-transmissivity regimes.

Contribution

It provides analytic upper bounds on channel capacity for electromagnetic channels, including those with amplification, applicable in practical noisy communication scenarios.

Findings

Upper bounds are tight in high-noise, low-transmissivity regimes.

Bounds are relevant for radio, infrared, and visible-wavelength free space channels.

Results help determine capacity limits for practical electromagnetic communication.

Abstract

We give analytic upper bounds to the channel capacity C for transmission of classical information in electromagnetic channels (bosonic channels with thermal noise). In the practically relevant regimes of high noise and low transmissivity, by comparison with know lower bounds on C, our inequalities determine the value of the capacity up to corrections which are irrelevant for all practical purposes. Examples of such channels are radio communication, infrared or visible-wavelength free space channels. We also provide bounds to active channels that include amplification.