Capacity Region of Gaussian MIMO Broadcast Channels with Common and Confidential Messages

TL;DR

This paper determines the full capacity region of a two-user Gaussian MIMO broadcast channel with both common and confidential messages, highlighting the secrecy constraints and their impact on communication limits.

Contribution

It provides the complete capacity region for Gaussian MIMO broadcast channels with confidential messages, connecting it to the known non-confidential case.

Findings

Exact capacity region derived for the channel with secrecy constraints

Insights into the relationship between confidential and non-confidential capacity regions

Enhanced understanding of secure communication limits in MIMO broadcast channels

Abstract

We study the two-user Gaussian multiple-input multiple-output (MIMO) broadcast channel with common and confidential messages. In this channel, the transmitter sends a common message to both users, and a confidential message to each user which needs to be kept perfectly secret from the other user. We obtain the entire capacity region of this channel. We also explore the connections between the capacity region we obtain for the Gaussian MIMO broadcast channel with common and confidential messages and the capacity region of its non-confidential counterpart, i.e., the Gaussian MIMO broadcast channel with common and private messages, which is not known completely.