Terahertz (THz) frequency band and free-space optical (FSO) communication can be proven potential solutions to the spectrum scarcity challenges in the emerging applications in the 6G. In this direction, a mixed THz-FSO relaying system is proposed in this paper. It is assumed that both THz and FSO links encounter fading effects and pointing errors, where the THz link is modeled using α-μ distribution while Málaga ( M ) distribution is used to characterize the FSO link. Particularly, we conduct the physical layer security (PLS) analysis and derive the secure outage probability into closed-form for two scenarios: 1) THz eavesdropping attack and 2) FSO eavesdropping attack. The effect of THz and FSO links parameters on the secrecy performance are then further investigated in detail. The results show that the security attacks on FSO links are more severe than those on THz links. Interestingly, the improved THz channel conditions adversely affect the security of the proposed mixed THz-FSO system, whereas better FSO channel conditions provide enhanced secrecy.
Terahertz (THz) frequency band and free-space optical (FSO) communication can be proven potential solutions to the spectrum scarcity challenges in the emerging applications in the 6G. In this direction, a mixed THz-FSO relaying system is proposed in this paper. It is assumed that both THz and FSO links encounter fading effects and pointing errors, where the THz link is modeled using α-μ distribution while Málaga ( M ) distribution is used to characterize the FSO link. Particularly, we conduct the physical layer security (PLS) analysis and derive the secure outage probability into closed-form for two scenarios: 1) THz eavesdropping attack and 2) FSO eavesdropping attack. The effect of THz and FSO links parameters on the secrecy performance are then further investigated in detail. The results show that the security attacks on FSO links are more severe than those on THz links. Interestingly, the improved THz channel conditions adversely affect the security of the proposed mixed THz-FSO system, whereas better FSO channel conditions provide enhanced secrecy.
Terahertz (THz) frequency band and free-space optical (FSO) communication can be proven potential solutions to the spectrum scarcity challenges in the emerging applications in the 6G. In this direction, a mixed THz-FSO relaying system is proposed in this paper. It is assumed that both THz and FSO links encounter fading effects and pointing errors, where the THz link is modeled using α-μ distribution while Málaga (M) distribution is used to characterize the FSO link. Particularly, we conduct the physical layer security (PLS) analysis and derive the secure outage probability into closed-form for two scenarios: 1) THz eavesdropping attack and 2) FSO eavesdropping attack. The effect of THz and FSO links parameters on the secrecy performance are then further investigated in detail. The results show that the security attacks on FSO links are more severe than those on THz links. Interestingly, the improved THz channel conditions adversely affect the security of the proposed mixed THz-FSO system, whereas better FSO channel conditions provide enhanced secrecy.
The use of the Terahertz (THz) frequency band and free-space optical (FSO) communication represents a promising solution to address the spectrum scarcity challenges encountered in emerging applications related to 6G. In this direction, a mixed THz-FSO relaying system is proposed in this paper. The study takes into account the presence of fading effects and pointing errors affecting both THz and FSO links. The THz link is modeled using α−μ distribution, while the FSO link is characterized using Malaga (M) distribution. The physical layer security (PLS) analysis is conducted, and secure outage probability is derived into closed-form for two scenarios: 1) THz eavesdropping attack and 2) FSO eavesdropping attack. The study further investigates the effect of THz and FSO links parameters on the secrecy performance in detail. The results demonstrate that security attacks on FSO links are more severe than those on THz links. Interestingly, improved THz channel conditions negatively affect the security of the proposed mixed THz-FSO system, whereas better FSO channel conditions provide enhanced secrecy.
In this paper, the secrecy performance of the physical layer security (PLS) of the hybrid free-space optical/radio frequency (FSO/RF) communication system is analyzed. The transmission protocol of the considered system is performed under the eavesdropper's attempt to overhear the RF link between the transmitter and legitimate receiver of the hybrid system. The FSO link is characterized by Málaga-M distribution while the RF links are modeled by Nakagami-m distribution. The two practical eavesdropping modes considered in this paper include: colluding and non-colluding. Exact closed-form expressions for the system's secrecy outage probability (SOP), the asymptotic of the SOP (SOP∞), the probability of strictly positive secrecy capacity (SPSC), the average secrecy capacity (ASC), and the asymptotic of the ASC (ASC∞), are specifically derived under the influence of both eavesdropper modes. Our derived analytical expressions present an efficient tool to investigate the impact of some channel parameters on the secrecy performance, namely the fading severity of the RF links, atmospheric turbulence severity, pointing error of the FSO link, number of eavesdroppers, and the power of the eavesdropper links. The results show that the increase of the eavesdroppers' number under both modes profoundly degrades the considered system secrecy performance. The accuracy of the numerical results obtained is validated by Monte-Carlo simulations.
The emergence of an array of new wireless networks has led researchers to evaluate the prospect of utilizing the physical properties of the wireless medium in order to design secure systems. In this paper, the physical layer secrecy performance of a mixed radio frequency-free space optical (RF-FSO) system with variable gain relaying scheme is investigated in the presence of an eavesdropper. We assume that the eavesdropper can wiretap the transmitted confidential data from the RF link only. It is further assumed that the main and eavesdropper RF links are modeled as generalized Gamma (GG) fading channel, and the free space optical (FSO) link experiences Málaga turbulence with pointing error impairment. Our primary concern is to protect this confidential information from being wiretapped. Besides pointing error, the atmospheric turbulence and two types of detection techniques (i.e. heterodyne detection and intensity modulation with direct detection) are also taken into consideration. Utilizing amplify-and-forward (AF) scheme, the novel mathematical closed-form expressions for average secrecy capacity, lower bound of secrecy outage probability, and strictly positive secrecy capacity are derived. As both the links (RF and FSO) undergo generalized fading channels, the derived expressions are also general. We present a unification of some existing works utilizing the proposed model to better clarify the novelty of this work. Finally, all the derived expressions are justified via Monte-Carlo simulations.
Increasing concerns regarding wireless systems' security are leading researchers to exploit the physical properties of a medium while designing any secured wireless network. The secrecy performance of a mixed radio frequency-free space optical (RF-FSO) system with a variable gain relaying scheme is investigated in this paper under the attempt of wiretapping by an eavesdropper. We assume that the eavesdropper can intrude the target data from the RF link only. Both the RF links (main and eavesdropper) undergo the α-μ fading statistics and the FSO link experiences the exponentiated Weibull fading statistics. Exploiting the amplify-and-forward (AF) relaying scheme while considering two detection techniques (i.e. heterodyne detection and intensity modulation/direct detection) with pointing error impairments, the mathematical formulations of the unified probability density function and cumulative distribution function are performed for the equivalent signal-to-noise ratio of the considered dual-hop RF-FSO link. Closed-form analytical expressions for average secrecy capacity, secrecy outage probability, and the probability of non-zero secrecy capacity are derived in terms of Meijer's G and Fox's H functions to quantify the system performance. Capitalizing on these expressions, the secrecy performance is further analyzed for various channel parameters of RF links, aperture sizes of the receiver, pointing errors, and atmospheric turbulence severity. The results reveal that aperture averaging can improve the secrecy performance remarkably by suppressing the effects of turbulence. Monte Carlo simulations are provided to justify the accuracy of the proposed model.
With the deployment of hybrid RF-FSO networks, there exists the potential to contribute significantly to the evolving landscape of 6G communication, as it effectively addresses challenges pertaining to connectivity, capacity, and security. In this paper, we study the secrecy performance of hybrid radio frequency (RF) - free space optical (FSO) systems in the presence of an eavesdropper. To improve the reliability of the source-destination transmission process, we consider a source that can transmit data via both RF and FSO links, simultaneously. Specifically, the RF links are exposed to generalized α – μ fading channels, while the FSO link is subject to Málaga distributions. Therefore, we deduce the novel analytical expression of secrecy outage probability and verify the results with the Monte Carlo simulations. The outcomes underscore the pronounced impact of fading parameters, receiver detection techniques, pointing errors, and atmospheric turbulence on security performance.