# Secure mmWave Communications in Cognitive Radio Networks

## TL;DR

This paper analyzes the secrecy outage probability of millimeter wave cognitive radio networks over fluctuating two-ray channels, providing exact and asymptotic formulas validated by simulations.

## Contribution

It derives the first exact and asymptotic expressions for SOP in FTR channels within CRNs, considering spectrum sharing and underlay power control.

## Key findings

- Exact SOP expression derived for FTR channels.
- Asymptotic SOP formula in high SNR regime.
- Simulation results confirm analytical accuracy.

## Abstract

In this letter, the secrecy performance in cognitive radio networks (CRNs) over fluctuating two-ray (FTR) channels, which is used to model the millimetre wave channel, is investigated in terms of the secrecy outage probability (SOP). Specifically, we consider the case where a source (S) transmits confidential messages to a destination (D), and an eavesdropper wants to wiretap the information from S to D. In a CRN framework, we assume that the primary user shares its spectrum with S, where S adopts the underlay strategy to control its transmit power without impairing the quality of service of the primary user. After some mathematical manipulations, an exact analytical expression for the SOP is derived. In order to get physical and technical insights into the effect of the channel parameters on the SOP, we derive an asymptotic formula for the SOP in the high signal-to-noise ratio region of the S--D link. We finally show some selected Monte-Carlo simulation results to validate the correctness of our derived analytical expressions.