Wireless Covert Communications Aided by Distributed Cooperative Jamming Over Slow Fading Channels

• Published in: IEEE transactions on wireless communications Vol. 20; no. 11; pp. 7026 - 7039
• Main Authors: Zheng, Tong-Xing, Yang, Ziteng, Wang, Chao, Li, Zan, Yuan, Jinhong, Guan, Xiaohong
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-11-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Channels; Communication; Communication system security; cooperative jamming; Covert communications; covert throughput; Error detection; Fading; Fading channels; jammer selection; Jammers; Jamming; Optimization; outage probability; Receivers; Security; Throughput; Transceivers; Wireless communication; Wireless communications
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2021.3080382

In this paper, we study covert communications between a pair of legitimate transmitter-receiver against a watchful warden over slow fading channels. There coexist multiple friendly helper nodes who are willing to protect the covert communication from being detected by the warden. We propose an uncoordinated jammer selection scheme where those helpers whose instantaneous channel gains to the legitimate receiver fall below a pre-established selection threshold will be chosen as jammers radiating jamming signals to defeat the warden. By doing so, the detection accuracy of the warden is expected to be severely degraded while the desired covert communication is rarely affected. We then jointly design the optimal selection threshold and message transmission rate for maximizing covert throughput under the premise that the detection error of the warden exceeds a certain level. Numerical results are presented to validate our theoretical analyses. It is shown that the multi-jammer assisted covert communication outperforms the conventional single-jammer method in terms of covert throughput, and the maximal covert throughput improves significantly as the total number of helpers increases, which demonstrates the validity and superiority of our proposed scheme.