Covert Wireless Communication With Spectrum Mask in Internet of Things Networks

• Published in: IEEE transactions on communications Vol. 69; no. 12; pp. 8402 - 8415
• Main Authors: Wang, Danyang, Qi, Peihan, Zhang, Ning, Si, Jiangbo, Li, Zan, Al-Dhahir, Naofal
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Covert communication; Error detection; improper Gaussian signaling; Interference; interference mitigation; Internet of Things; Optimization; power allocation; Security; Signaling; spectrum mask; Throughput; Transmitters; Uncertainty; Wireless communication; Wireless communications; Wireless networks
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2021.3116162

Covert wireless communications aim to hide the existence of transmission behavior from watchful adversaries to enhance security. In this paper, we propose a spectrum mask based covert communication strategy in Internet of Things (IoT) networks, where the overt channels are leveraged to enhance the covertness. Specifically, the legitimate IoT transmitter superimposes its own message on the overt channel to avoid being detected by the warden. We assume that proper Gaussian signaling (PGS) is adopted at the overt channel, and improper Gaussian signaling (IGS) is adopted at the legitimate transmitter to improve the covert transmission performance. To maximize the covert rate of the legitimate IoT system, a joint transmit power and IGS factor optimization problem is formulated under the constraints of covertness requirement. The metric of minimum error detection probability, that represents the worst-case for the legitimate transmitter, is utilized to measure the covertness. By exploiting the piece-wise monotonic properties of the objective function and the constraints, we derive the optimal transmit power and IGS factor pairs in both the IGS and PGS schemes. Finally, extensive numerical results are presented to demonstrate that the IGS scheme can improve the covert rate compared to the PGS scheme under a given covertness constraint.