Physical Layer Authentication Exploiting Antenna Mutual Coupling Effects in mmWave Systems

Impersonation attacks pose a significant threat to millimeter wave (mmWave) wireless systems due to the unique characteristics (e.g., highly directional beams) of mmWave communications. To this end, this paper proposes a novel physical layer authentication (PLA) scheme that leverages the antenna array-specific mutual coupling (MC) feature to validate the identity of the transmitter. In particular, we first demonstrate the authentication feasibility of the MC feature by modeling its amplitude and phase characteristics using generalized Gaussian and Laplace distributions, respectively. Then, based on the amplitude and phase of the MC feature, we design a kernel-based authentication scheme to further improve device distinguishability in mmWave systems. Moreover, we provide analytical expressions of the false alarm and detection probabilities, enabling a theoretical characterization of the proposed authentication scheme performance. Finally, numerical results are provided to verify the reliability and effectiveness of the proposed authentication scheme under various settings. The results indicate that the proposed scheme can provide performance gain compared to the single-dimensional feature-based schemes under different signal–noise ratio scenarios.