A Survey on Methods to Detect Pilot Contamination Attack against Physical Layer Authentication

A promising strategy to authenticate users’ identity in next generation wireless systems is by physical layer authentication (PLA) techniques. One way to accomplish authentication at the physical layer relies on comparison of the currently estimated instantaneous channel features, such as amplitude or frequency response, and those obtained during training: a hypothesis testing is applied whose optimal results are subject to the choice of the threshold value used in the comparison. By initiating pilot contamination attack (PCA) against the process of channel estimation, a non-authenticated user can corrupt the channel state information-based PLA mechanism. This way, identification fails and the intruder improves its substitution and impersonation capabilities. To secure the system against such types of malicious intervention, the methods to detect and counteract pilot contamination against PLA must be extensively studied. In this paper, an overview of several most significant methods related to PCA detection is presented together with an analysis of their characteristics.