Artificial Noise Versus Artificial Noise Elimination: Redefining Scaling Laws of Physical Layer Security

TL;DR

This paper establishes scaling laws for physical-layer security in wireless MIMO channels, analyzing the effects of artificial noise and its elimination on secrecy rates and system design.

Contribution

It introduces new scaling laws and corollaries that reveal the interplay between transmit, receive, and eavesdropper antennas, and the effectiveness of artificial noise elimination strategies.

Findings

When eavesdropper has more than twice the antennas of the transmitter, secure communication may be impossible.

Artificial noise remains effective under certain conditions even with advanced elimination strategies.

Guidelines for system design are provided considering artificial noise and elimination tactics.

Abstract

Artificial noise (AN) is a key physical-layer security scheme for wireless communications over multiple-input multiple-output wiretap channels. Recently, artificial noise elimination (ANE) has emerged as a strategy to mitigate the impact of AN on eavesdroppers. However, the influence of ANE on the secrecy rate when counteracting AN has not been investigated. In this paper, we address this issue by establishing scaling laws for both average and instantaneous secrecy rates in the presence of AN and ANE. Based on the scaling laws, several derived corollaries provide insights into the mutual constraints between the number of transmit antennas, receive antennas, and antennas at eavesdroppers, revealing the interplay between these factors. A key corollary reveals that when the eavesdropper possesses more than twice as many antennas as the transmitter, secure communication may no longer be guaranteed. Additionally, by comparing scenarios where ANE counteracts AN with those where AN is not employed, this study identifies sufficient conditions under which AN remains effective. Finally, the derived secrecy rates provide guidelines for system design, even in the presence of advanced ANE countermeasures implemented by the eavesdropper.