3-Receiver Broadcast Channels with Common and Confidential Messages

TL;DR

This paper derives inner bounds on the secrecy capacity regions for a 3-receiver broadcast channel with common and confidential messages, introducing new coding strategies and demonstrating tight bounds in specific scenarios.

Contribution

It introduces new inner bounds for secrecy capacity in 3-receiver broadcast channels with confidential messages, using innovative coding techniques and establishing tight bounds in certain cases.

Findings

Inner bounds are tight for reversely degraded channels.

Secrecy is achievable using superposition coding and indirect decoding.

Bounds are tight when legitimate receivers are less noisy than the third receiver.

Abstract

This paper establishes inner bounds on the secrecy capacity regions for the general 3-receiver broadcast channel with one common and one confidential message sets. We consider two setups. The first is when the confidential message is to be sent to two receivers and kept secret from the third receiver. Achievability is established using indirect decoding, Wyner wiretap channel coding, and the new idea of generating secrecy from a publicly available superposition codebook. The inner bound is shown to be tight for a class of reversely degraded broadcast channels and when both legitimate receivers are less noisy than the third receiver. The second setup investigated in this paper is when the confidential message is to be sent to one receiver and kept secret from the other two receivers. Achievability in this case follows from Wyner wiretap channel coding and indirect decoding. This inner bound is also shown to be tight for several special cases.