Covert Capacity of Degraded Broadcast Channels

TL;DR

This paper derives the covert capacity region of degraded broadcast channels, showing that superposition coding outperforms time-sharing for undetectable communication.

Contribution

It provides a computable capacity region for covert communication over degraded broadcast channels, highlighting the superiority of superposition coding over time-sharing.

Findings

Superposition coding achieves higher covert rates than time-sharing.

The capacity region is expressed in a computable form.

Numerical results demonstrate the advantage of superposition coding.

Abstract

We derive the capacity region of the degraded broadcast channel (DBC) subject to the constraint that the communication is not detected by an adversary, the Warden. Our capacity result is in a computable form and numerical results show that time-sharing is suboptimal in general, and improved rates can be obtained through superposition coding.