Analysis of a covert communication method utilizing non-coherent DPSK masked by pulsed radar interference

Abstract

In this paper, a covert communication method is proposed that embeds a digital communication signal onto the radar return of a pulse Doppler radar. The interfering radar signal at the receiver is estimated and coherently subtracted from combined signal prior to demodulation of the communications signal to baseband and symbol detection. The robustness of the communication method to various estimation errors is investigated for several phase shift keying digital communication modulations through Monte Carlo simulations. It is demonstrated that differential encoding systems with non-coherent detection perform best in the presence of frequency estimation errors. However, it was also demonstrated that the system is not very robust to phase estimation errors. The performance of non-coherent differential phase shift keying and differential quaternary phase shift keying are investigated to determine the impact of varying different parameters upon symbol error rate.