On Secrecy Metrics for Physical Layer Security over Quasi-Static Fading Channels

TL;DR

This paper introduces three new secrecy metrics for physical layer security over quasi-static fading channels, addressing limitations of the traditional secrecy outage probability by providing insights into eavesdropper decodability and information leakage.

Contribution

It proposes three novel secrecy metrics that offer a more comprehensive understanding of security performance and aid in designing secure wireless systems.

Findings

The first metric links secrecy outage to eavesdropper decodability.

The second metric is based on error probability for practical security.

The third metric measures the rate of information leakage.

Abstract

Theoretical studies on physical layer security often adopt the secrecy outage probability as the performance metric for wireless communications over quasi-static fading channels. The secrecy outage probability has two limitations from a practical point of view: a) it does not give any insight into the eavesdropper's decodability of confidential messages; b) it cannot characterize the amount of information leakage to the eavesdropper when an outage occurs. Motivated by the limitations of the secrecy outage probability, we propose three new secrecy metrics for secure transmissions over quasi-static fading channels. The first metric establishes a link between the concept of secrecy outage and the decodability of messages at the eavesdropper. The second metric provides an error-probability-based secrecy metric which is typically used for the practical implementation of secure wireless systems. The third metric characterizes how much or how fast the confidential information is leaked to the eavesdropper. We show that the proposed secrecy metrics collectively give a more comprehensive understanding of physical layer security over fading channels and enable one to appropriately design secure communication systems with different views on how secrecy is measured.