Secrecy Degradation for Inevitable Phase Noise in Artificial Noise Shielded FH Systems

Abstract

This paper adopts an artificial noise (AN) shielded frequency hopping (FH) architecture to counteract both wire-tapping and hostile attack, but the inevitable phase noise will degrade both the AN cancellation and secrecy performance. Considering this, first, the AN cancellation performance is analyzed by separating the received AN into the cancellable common phase component (CPC) and non-cancellable inter-carrier interference (ICI). On top of this, the system secrecy is analyzed via secrecy capacity, and the secrecy degradation for phase noise is extracted in terms of 3 dB coherence bandwidth of the adopted oscillators, transmitting power ratio of AN to expected signal (ES), propagation channel quality, and parameter estimation period. Numerical and simulation results show that phase noise will degrade both the AN cancellation and secrecy performance, and this degradation can be diminished by shortening the parameter estimation period, optimizing the power ratio of AN to ES, and improving the propagation channel quality.