Robust Tracking-Based PHY-Authentication in mmWave MIMO Systems

Physical Layer Authentication (PLA) is a topic of considerable interest in ensuring strong security for upcoming wireless networks. However, existing PLA methods face challenges in maintaining performance in dynamic environments. To overcome this, we propose a novel tracking-based PLA approach, utilizing properties of the beamspace multiple-input multiple-output (MIMO) channel in narrowband millimeter-wave (mmWave) networks. Specifically, In particular, the proposed technique involves extracting a distance signature vector from the positions of the principal components within the beamspace MIMO channel representation. These components are then sorted in descending order based on their indices. To address mobility concerns in dynamic settings, a tracking filter is introduced. This filter allows the authentication system to continuously track and update the stored signature, enhancing overall authentication performance. Additionally, the proposed technique is extended to ultra-wideband signaling. In this extension, the richness of the derived signature is further improved by exploiting the beam squint effect, contributing to a more robust authentication process. Simulation results demonstrate that our approach overcomes the limitations of previous methods, resulting in improved authentication performance measured by detection and false alarm rates.

I. Introduction

Over the past few decades, wireless communication technologies have made significant advancements in both reliability and data throughput. These advancements have been made feasible through the utilization of two key innovations: multiple-input multiple-output (MIMO) systems and millimeter wave (mmWave) technology. However, security remains a critical concern in these deployments due to the open and broadcast nature of the wireless medium, which makes it vulnerable to various threats from illegitimate nodes, such as spoofing and Sybil attacks. In a spoofing attack, the attacker attempts to corrupt legitimate communications by injecting some forged identity information, while the Sybil attack is based on creating multiple fake identities that are designed to appear as distinct legitimate participants, giving the attacker the ability to manipulate network activities [1]. In recent years, physical layer authentication (PLA) has emerged as an additional security measure to complement conventional cryptography-based techniques to provide authentication against different security threats. PLA provides a fast, cost-effective, and low-complexity computational security solution, besides its compatibility with forthcoming wireless communication networks such as 6G and beyond. PLA leverages the random nature of the wireless medium and the hardware impairments of the transceiver terminals [2] without the requirement of additional security information, which significantly the available capacity of the channel and improves the system’s immunity against various security vulnerabilities.