Analysis of eavesdropping attack in mmWave-based WPANs with directional antennas

Abstract

This paper explores the benefits of using directional antennas in an eavesdropping attack in millimeter-wave (mmWave)-based wireless personal area networks (WPANs) and the security enhancement of mmWaves. The detection and protection probabilities are analyzed for the eavesdropper's and transmitter's perspectives, respectively. The analysis is based on the probability density function of distance between devices (DEVs), the exposure region, and the interference free (limited) exposure region of a DEV. Four cases, in which all target DEVs and an eavesdropper are equipped with either a directional antenna or an omni-directional antenna, are considered in a single-hop and a multi-hop communications. The expected lower bound of an eavesdropper's detection probability and the relative detection rate are presented. Numerical results show that there exists a number of DEVs such that an eavesdropper can detect DEVs maximally. The detection probability tends to zero in a single-hop case, while it is saturated in a multi-hop case, as the number of DEVs increases. A DEV can communicate safely in one hop, while the communication is not secure anymore after several hops. Based on these results, we can conclude that the use of a directional antenna enables the better protection from an eavesdropping attack in mmWave-band communication and mmWave band can improve the security in communication.