Channel State Information Based Optimal Strategy for Covert Communication

Abstract

Covert communication aims at achieving a reliable communication while ensuring an arbitrary small probability of being detected by the adversary. In this paper, we exploit the channel state information (CSI) to further improve the performance of covert communication. We propose two strategies, namely, the Transmission Time Selection Strategy (TTSS) and the Power Control Strategy (PCS). In TTSS the transmission turns on only when the channel is good enough, while in PCS the transmission power changes with the channel gain. Besides, to obtain a positive information rate, a full-duplex receiver is considered, which sends jamming signal to confuse the adversary. The detection performances are analysed and the optimal parameters of the transmission strategies are determined. Numerical results show the relationships between the effective rate and the covert constraint.