Secrecy Performance of Terahertz Wireless Links in Rain and Snow

TL;DR

This paper investigates the physical layer security of terahertz wireless links in adverse weather conditions like rain and snow, analyzing how weather-induced signal degradation impacts secrecy capacity and eavesdropping vulnerability.

Contribution

It provides a theoretical model for THz link secrecy performance in rain and snow, including effects of weather particles, gaseous attenuation, and beam divergence, with comparative analysis at multiple frequencies.

Findings

THz links are less vulnerable to eavesdropping in rain.

Higher carrier frequencies reduce maximum data rates in adverse weather.

Secrecy capacity decreases with increasing frequency in rain and snow.

Abstract

Wireless communication technique at terahertz (THz) frequencies is regarded as the most potential candidate for future wireless networks due to its wider frequency bandwidth and higher data capacity when compared to that employing radio frequency (RF) and millimeter wave (mmWave). Besides, a THz link can achieve higher security at physical layer when it propagates in clear weather due to its higher directionality, which reduces the possibility of eavesdropping attacks. However, under adverse weather conditions (such as water fog, dust fog, rain and snow), the link degradation due to weather particles and gaseous molecules will affect the link secrecy performance seriously. In this work, we present theoretical investigations on physical layer security of a point-to-point THz link in rain and snow with a potential eavesdropper locating outside of the legitimate link path. Signal degradation due to rain/snow, gaseous attenuation and beam divergence are included in a theoretical model to estimate the link performance. Secrecy capacity of the link with carriers at 140, 220 and 340 GHz is calculated and compared. Insecure regions are also presented and the secrecy performance is analyzed. We find that the THz link suffers least eavesdropping attacks in rain and the maximum data transmission rate decreases for higher carrier frequencies in rain and snow.