Intelligent covert communication design for cooperative cognitive radio network

Extensive research attentions have been devoted to studying cooperative cognitive radio networks (CCRNs), where secondary users (SU) providing cooperative transmissions can be permitted by primary users (PU) to use spectrum. In order to maximize SU's utility, SU may transmit its own information during the period of cooperative transmission, which stimulates the use of covert transmission against PU's monitoring. For this sake, this article reviews the motivations of studying covert communications in CCRN. In particular, three intelligent covert transmission approaches are developed for maximizing SU's utility in CCRNs, namely, intelligent parasitic covert transmission (IPCT), intelligent jammer aided covert transmission (IJCT) and intelligent reflecting surface assisted covert transmission (IRSC). Further, some raw performance evaluations are discussed, and a range of potential research directions are also provided.