Danyang Wang, Jinxiu Wang, Xinyu Zhao, Ning Zhang, Hong-Ning Dai, and Zan Li
IEEE International Conference on Communications (ICC), 2022
Publication year: 2022

In this paper, we study the information freshness on covert communication in the Internet of Things (IoT) networks. The freshness of information is characterized by a recently introduced metric, termed as age of information (AoI). Specifically, without a feedback channel, each packet generated at the transmitter is only allowed to be transmitted during one time slot no matter whether it is successfully decoded at the receiver. In this case, the average AoI at the receiver and the average probability of error detection at the warden are derived. Then, the transmit power is optimized to minimize the AoI while guaranteeing the covertness requirement. On the other hand, with a perfect feedback channel, packet re-transmission is adopted to make the information fresh enough. The average AoI and the average probability of error detection are analyzed. Then, the transmit power is also optimized in this case. Simulation results reveal that the proposed scheme can minimize average AoI under the requirement of covertness, and the case using re-transmission with feedback achieves a lower AoI under the same requirement of covertness.