Multiple Antenna Secure Broadcast over Wireless Networks

TL;DR

This paper investigates secure multi-antenna broadcast communication over wireless networks, deriving bounds and coding schemes to ensure confidentiality for multiple users in the presence of eavesdroppers.

Contribution

It introduces a computable outer bound on secrecy capacity and develops a secure dirty-paper coding scheme for multi-antenna broadcast channels.

Findings

The Sato-type outer bound aligns with the achievable rate region.

A simplified dirty-paper coding scheme achieves reliable secrecy.

Numerical examples validate the theoretical bounds.

Abstract

In wireless data networks, communication is particularly susceptible to eavesdropping due to its broadcast nature. Security and privacy systems have become critical for wireless providers and enterprise networks. This paper considers the problem of secret communication over the Gaussian broadcast channel, where a multi-antenna transmitter sends independent confidential messages to two users with perfect secrecy. That is, each user would like to obtain its own message reliably and confidentially. First, a computable Sato-type outer bound on the secrecy capacity region is provided for a multi-antenna broadcast channel with confidential messages. Next, a dirty-paper secure coding scheme and its simplified version are described. For each case, the corresponding achievable rate region is derived under the perfect secrecy requirement. Finally, two numerical examples demonstrate that the Sato-type outer bound is consistent with the boundary of the simplified dirty-paper coding secrecy rate region.