Covert Communication Based on Non-Ideal Detection of Overt Channels

In this paper, we study a covert communication strategy based on non-ideal detection on overt channels in Internet of Things (IoT) networks, where IoT device utilizes existing overt channels as spectrum masks to achieve covert communication. We consider the non-ideal detection of IoT device on overt channels. At the same time, to improve covert transmission rate, we use improper Gaussian signaling (IGS) at IoT device. We first provide detection errors of IoT device, and then analyze the non-ideal transmission rate using IGS and minimum error detection probability of the warden. Next, we jointly optimize the transmit power of IoT device and circularity coefficient of IGS to maximize the covert rate while meeting the quality of service (QoS) constraint of the overt channel and the covertness constraint. The final simulations demonstrate that considering the non-ideal detection of IoT device and utilizing IGS can effectively improve the system transmission rate.