Covert Communications Without Pre-Sharing of Side Information and Channel Estimation Over Quasi-Static Fading Channels

TL;DR

This paper introduces a covert communication method that does not require pre-shared information or channel estimation, using Grassmann constellations for noncoherent detection to enhance covertness and data rates.

Contribution

It presents a novel covert scheme leveraging Grassmann manifolds, enabling unshared randomization and eliminating pilot symbols, improving covertness and rate without added complexity.

Findings

Higher covertness compared to conventional schemes

Achieves better data rates without pre-shared information

No additional complexity introduced

Abstract

We propose a new covert communication scheme that operates without pre-sharing side information and channel estimation, utilizing a Gaussian-distributed Grassmann constellation for noncoherent detection. By designing constant-amplitude symbols on the Grassmann manifold and multiplying them by random variables, we generate signals that follow an arbitrary probability distribution, such as Gaussian or skew-normal distributions. The mathematical property of the manifold enables the transmitter's random variables to remain unshared with the receiver, and the elimination of pilot symbols that could compromise covertness. The proposed scheme achieved higher covertness and achievable rates compared to conventional coherent Gaussian signaling schemes, without any penalty in terms of complexity.