Covert Capacity of Degraded Broadcast Channels

2026-05-10

AI Summary

This work investigates the covert communication capacity region of a degraded broadcast channel in the presence of a warden. By leveraging information-theoretic analysis and superposition coding, the study derives—for the first time—an analytically tractable and exact characterization of the capacity region under a covertness constraint. The results demonstrate that conventional time-sharing strategies are generally suboptimal, whereas superposition coding substantially enhances achievable transmission rates. Numerical experiments corroborate the superiority of the proposed scheme in terms of covert communication performance, offering both theoretical foundations and practical design guidelines for multiuser covert transmission systems.

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.

Problem

• covert communication
• degraded broadcast channel
• capacity region
• undetectable communication
• information-theoretic security

Innovation

• covert communication
• degraded broadcast channel
• superposition coding
• capacity region
• undetectable transmission