Covert Capacity of Non-Coherent Rayleigh-Fading Channels

TL;DR

This paper characterizes the maximum covert communication rate over non-coherent Rayleigh-fading channels, providing bounds and conjectures on optimal input distributions for secure wireless communication.

Contribution

It introduces the covert capacity for non-coherent Rayleigh-fading channels and proposes finite-mass point input distributions, including a conjecture on their optimality.

Findings

Covert capacity achieved with finite mass point distributions.

Numerically tractable bounds on covert capacity provided.

Conjecture that two-mass point distributions are optimal.

Abstract

The covert capacity is characterized for a non-coherent fast Rayleigh-fading wireless channel, in which a legitimate user wishes to communicate reliably with a legitimate receiver while escaping detection from a warden. It is shown that the covert capacity is achieved with an amplitude-constrained input distribution that consists of a finite number of mass points including one at zero and numerically tractable bounds are provided. It is also conjectured that distributions with two mass points in fixed locations are optimal.