A PHY Layer Security of a Jamming-Based Underlay Cognitive Satellite-Terrestrial Network

• Published in: IEEE transactions on cognitive communications and networking Vol. 7; no. 4; pp. 1266 - 1279
• Main Authors: Bouabdellah, Mounia, Bouanani, Faissal El
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.12.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cognitive radio networks; eavesdropping; Fading; free-space optics; Ground stations; intercept probability; Interference; IP networks; Jammers; Jamming; jamming signals; Optical transmitters; Parameters; physical layer security; Protocols; Relay satellites; satellite communication; Satellites; Security; Signal to noise ratio
• ISSN: 2332-7731; 2332-7731
• DOI: 10.1109/TCCN.2021.3074909

In this work, we investigate the physical layer security of a jamming-based underlay cognitive satellite-terrestrial network consisting of a radio frequency link at the first hop and an optical feeder at the second hop. Particularly, one secondary user (SU) is transmitting data to an end-user optical ground station through the aid of a relay satellite, in the presence of an active eavesdropper at each hop. Moreover, another SU located in the first hop is acting as a friendly jammer and continuously broadcasting an artificial noise that cannot be decoded by the wiretapper so as to impinge positively on the system's secrecy. Owing to the underlying strategy, the SUs are permanently adjusting their transmit powers in order to avoid causing harmful interference to primary users. The RF channels undergo shadowed-Rician and Rayleigh fading models, while the optical link is subject to Gamma-Gamma turbulence with pointing error. Closed-form and asymptotic expressions for the intercept probability (IP) are derived considering two different scenarios regardless of the channel's conditions, namely (i) absence and (ii) presence of a friendly jammer. The effect of various key parameters on IP, e.g., sources' transmit power, artificial noise, maximum tolerated interference power, and fading severity parameters are examined. Precisely, we aim to answer the following question: could a friendly jammer further enhance the security of such a system even in a low SNR regime? All the derived results are corroborated by Monte Carlo simulations and new insights into the considered system's secrecy are gained.