This paper examines how residual hardware impairments (RHI) influence the reliability of physical-layer authentication (PLA) in wireless systems enhanced by Reconfigurable Intelligent Surfaces (RIS). The study considers a scenario where a legitimate user and an attacker communicate with a receiver through an RIS, with no direct line-of-sight links available. Because authentication depends on accurately estimating channel characteristics, distortions introduced by imperfect hardware play a critical role in determining whether a receiver can distinguish between genuine and spoofed signals. To model realistic conditions, the authors incorporate RHI at both the transmitter and receiver and analyze their impact on the likelihood ratio–based authentication test. Channel dynamics are represented using an autoregressive model, and the RIS assists the communication by introducing programmable reflections that shape the effective channel observed at the receiver.
The results show that RIS can significantly strengthen authentication, even in the presence of hardware imperfections. Increasing the number of RIS elements improves the distinguishability between legitimate and adversarial signals, reducing the miss detection rate for a given false alarm level. The paper also highlights that hardware impairments affect legitimate users and attackers differently; when an attacker’s hardware distortions are larger, spoofing becomes easier to detect. Higher SNR conditions further improve authentication accuracy, and RIS configurations optimized for the legitimate user outperform blind or non-assisted setups. Overall, the study demonstrates that RIS not only enhances wireless coverage but also contributes meaningfully to physical-layer security. By understanding how hardware quality and RIS design interact, network designers can build more robust authentication mechanisms for future wireless systems.
Impact_of_Residual_Hardware_Impairments_on_RIS-Aided_Authentication