On the Statistical Behavior of CP-Based Artificial Noise at the Receiver-Side in PLC Systems

This paper analyzes the statistical behavior of the cyclic prefix (CP)-based artificial noise (AN) from the eavesdropper's perspective to evaluate physical-layer security in power line communication (PLC) systems. The received AN is modeled as a random vector, and its analysis is based on the derivation of first- and second-order statistical moments. Numerical results across narrowband and broadband PLC channels show that, despite being theoretically zero-mean, residual structures emerge in practice. Moreover, the analysis reveals that the transmitter's null-space projection introduces non-negligible cyclic correlation patterns. These structural characteristics indicate that the received AN is not strictly random, representing a critical vulnerability that an eavesdropper could potentially exploit to perform a security breach.