Jamming-Assisted Short Packet Covert Communications in Multi-Hop Wireless Networks

In this paper, we investigate a scenario, where the legitimate users adopt the decode-and-forward (DF) strategy for multi-hop transmission covertly assisted by a jammer, against a flying warden (Willie). For the considered scenario, the detection performance at Willie and the lower bound for the covert constraint are derived, based on which, the expressions for the optimal transmit power and the optimal number of relays for reliable transmission satisfying the covert constraint are obtained. It is found that there is an optimal location for a fixed power jammer to maximize the effective covert throughput. Furthermore, simulation results prove our analysis and show that there is an optimal transmit power and an optimal number of relays to maximize the effective covert throughput.