This paper investigates the secrecy performance for a decode-and-forward (DF) based mixed radio-frequency (RF) and free-space-optics (FSO) cooperative wireless network. The Rayleigh distribution is used to characterize the RF channel, similarly the turbulence effect in the FSO link is characterized by double-generalized-Gamma (DGG) distribution. The effect of pointing error is included during analysis. The closed form expressions of outage-probability for secrecy (SOP) and probability of non-zero secrecy capacity or strictly-positive-secrecy-capacity (SPSC) are analysed in terms of Meijer'G function. Finally all of the aforementioned results are verified via Monte-Carlo simulation.
This paper investigates the secrecy performance for a decode-and-forward (DF) based mixed radio-frequency (RF) and free-space-optics (FSO) cooperative wireless network. The Rayleigh distribution is used to characterize the RF channel, similarly the turbulence effect in the FSO link is characterized by double-generalized-Gamma (DGG) distribution. The effect of pointing error is included during analysis. The closed form expressions of outage-probability for secrecy (SOP) and probability of non-zero secrecy capacity or strictly-positive-secrecy-capacity (SPSC) are analysed in terms of Meijer'G function. Finally all of the aforementioned results are verified via Monte-Carlo simulation.
In this paper, the secrecy performance of a mixed radio frequency-free space optical (RF-FSO) communication system that consists of a source (S), a relay (R), a destination (D), and an eavesdropper (E), is studied. In this system, it is assumed that the E can overhear the free space optical (FSO) link between R and D as it is close to D. It is further assumed that the radio frequency (RF) and FSO links experience Rayleigh and Gamma-Gamma fading, respectively. Considering atmospheric turbulence, pointing errors, two types of detection techniques, and decode-and-forward scheme, the closed-form expressions for the lower bound of secrecy outage probability and the probability of strictly positive secrecy capacity are derived. Monte Carlo simulation results are also presented to validate the accuracy of the derivations.
In this paper, we investigate a secure dual-hop radio frequency-free space optical (RF-FSO) mixed variable gain relaying framework in the presence of a single eavesdropper. The RF and FSO links are modeled with hyper Gamma (HG) and Gamma-Gamma (ΓΓ) fading channels, respectively. We assume that the eavesdropper utilizes another HG fading channel to wiretap the transmitted confidential data from the RF link. Our key concern is to defend this information against passive eavesdropping. We carry out the secrecy measurements by deriving closed-form mathematical expressions of average secrecy capacity (ASC), secure outage probability (SOP), and strictly positive secrecy capacity (SPSC), all in terms of Meijer's G function. Capitalizing on the derived expressions, we analyze the impacts of atmospheric turbulence and pointing errors on the secrecy capacity and outage performance of the proposed scenario. For gaining more insights, we also analyze the asymptotic outage behaviour for high signal-to-noise ratio. Two detection techniques i.e. heterodyne (HD) and the intensity modulation with direct detection (IM/DD) are taken into consideration and our results demonstrate that HD technique notably outperforms the IM/DD scheme. The supremacy and novelty of the model is demonstrated via utilizing generic properties of the HG fading channel. Finally, we provide a justification of the derived expressions via Monte-Carlo simulations.
In this letter, the secrecy performance of a decode-and-forward (DF) principle based mixed free space optics (FSO) and radio frequency (RF) system is analyzed. The analysis is done from physical layer (PHY) security perspective. Herein, two different eavesdroppers are considered while signal is transmitting from source (S) to destination (D) through a relay (R) point. The FSO based and RF based eavesdroppers are trying to intercept the confidential signal from S-R link and R-D links respectively. The faded FSO links are modeled by Málaga (M) distribution and RF links are characterized by Nakagami-m distribution. Exact closed form expression for secrecy performance metric such as secrecy outage probability is derived and analyzed for the aforementioned system in terms of Meijer's G-function and bivariate Fox's H-function. Furthermore, the asymptotic expressions for these performance metrics are derived by employing high signal to noise ratio (SNR) approximation. Afterwards the results are verified by Monte-Carlo simulations. Finally, the secrecy threshold for the system is derived to get insight of the system reliability and secrecy.
Effects of Eavesdropper on the Performance of Mixed η–μ and DGG Cooperative Relaying System
Free-space optical (FSO) channels offer line-of-sight wireless communication with high data rates utilizing unlicensed optical spectrum. The hybrid radio frequency (RF)–FSO system is currently receiving a great deal of research interest because atmospheric turbulence prevents enhanced secrecy performance. Except for the double generalized gamma (DGG) model, traditional FSO models typically are unable to show secrecy performance across all turbulence severity ranges. Due to this, we propose a dual-hopη–μand unified DGG mixed RF–FSO network while taking into account the following three different eavesdropping scenarios: 1) the eavesdropper is at the RF link; 2) the eavesdropper is at the FSO link; and 3) both eavesdroppers remains active simultaneously. These proposed scenarios' security is examined in terms of the probability, of strictly positive secrecy capacity, secure outage probability and effective secrecy throughput, and further investigation is done into the implications of various system settings on the secrecy performance. The analysis shows that, when compared to the other two scenarios, the third scenario exhibits the worst secrecy condition. Intensity modulation/direct detection (IM/DD) and heterodyne detection (HD) approaches are compared, with HD outperforming IM/DD in terms of secrecy performance. Finally, Monte Carlo simulations are used to confirm all analytical findings.
We investigate the physical-layer security performance for a wireless-powered relaying mixed free-space optical-radio frequency (FSO-RF) system. In this system, a source transmits optical information to a relay (R), which decodes the received signal with a decode-and-forward protocol, converts it into an RF signal, and forwards it to a destination in the presence of an eavesdropper. Furthermore, we also assume that R has no extra power supply, and it only relies on harvesting energy from a power beacon to forward the information. Assuming that the FSO and all of the RF channels experience gamma-gamma and Rayleigh fading, the closed-form analytical expressions for secrecy outage probability and the probability of strictly positive secrecy capacity are derived. In addition, the effects of atmospheric turbulence, pointing errors, and detection techniques on the system performance are analyzed. Finally, we perform Monte Carlo simulations to verify the accuracy of the derived expressions.
Free-space optical (FSO) channel offers line-of-sight wireless communication with high data rates and high secrecy utilizing unlicensed optical spectrum and also paves the way to the solution of the last-mile access problem. Since atmospheric turbulence is a hindrance to an enhanced secrecy performance, the mixed radio frequency (RF)-FSO system is gaining enormous research interest in recent days. But conventional FSO models except for the double generalized Gamma (DGG) model can not demonstrate secrecy performance for all ranges of turbulence severity. This reason has led us to propose a dual-hop eta-mu and unified DGG mixed RF-FSO network while considering eavesdropping at both RF and FSO hops. The security of these proposed scenarios is investigated in terms of two metrics, i.e., strictly positive secrecy capacity and secure outage probability. Exploiting these expressions, we further investigate how the secrecy performance is affected by various system parameters, i.e., fading, turbulence, and pointing errors. A demonstration is made between heterodyne detection (HD) and intensity modulation and direct detection (IM/DD) techniques while exhibiting superior secrecy performance for HD technique over IM/DD technique. Finally, all analytical results are corroborated via Monte-Carlo simulations.