Defining Spatial Security Outage Probability for Exposure Region Based Beamforming

TL;DR

This paper introduces the Spatial Secrecy Outage Probability (SSOP) to quantify security in beamforming systems, analyzing how antenna array parameters influence security performance in Rician fading channels.

Contribution

It formalizes the SSOP concept and provides a theoretical framework to analyze how array parameters affect security, including an analytic upper bound in Rician fading.

Findings

SSOP depends on antenna array parameters.

Analytic upper bound for SSOP is derived.

Security performance varies with array configuration in Rician channels.

Abstract

With increasing number of antennae in base stations, there is considerable interest in using beamfomining to improve physical layer security, by creating an `exposure region' that enhances the received signal quality for a legitimate user and reduces the possibility of leaking information to a randomly located passive eavesdropper. The paper formalises this concept by proposing a novel definition for the security level of such a legitimate transmission, called the `Spatial Secrecy Outage Probability' (SSOP). By performing a theoretical and numerical analysis, it is shown how the antenna array parameters can affect the SSOP and its analytic upper bound. Whilst this approach may be applied to any array type and any fading channel model, it is shown here how the security performance of a uniform linear array varies in a Rician fading channel by examining the analytic SSOP upper bound.