Covert UAV Communication by Exploiting Imperfect Cancellation Under Channel Uncertainty

Covert communication has emerged as a promising scheme to protect the communication process from being detected by illegal users with arbitrarily small probability. In this paper, we study the problem of hiding private messages under public signals in a remote Unmanned Aerial Vehicles (UAV) communication system, by taking advantage of the uncertainty of fading channels. Specifically, we first propose a theoretical model for such a covert transmission system, where the channel uncertainty resulting from channel estimation error is considered. Thus, imperfect cancellation of public signals can be exploited to deteriorate the detection performance of illegal users. Then, under such conditions, the performance of covertness and reliability of covert communication over fading channels is analyzed, where the detection probability and the outage probability are derived, respectively. Finally, numerical results demonstrate that the detection probability can be decreased under fading channels, which as a result raises the covertness of UAV communication.