This paper constructs a radio frequency (RF)/free space optical (FSO) system for the hybrid satellite-terrestrial relay network (HSTRN), which applies the decode and forward protocol. The shadowed Rician (SR) and Gamma-Gamma (GG) distribution are used to portray the fading of RF and FSO links. The secrecy outage probability (SOP) of the HSTRN system is calculated in this paper. We deduce the closed-form expression of SOP. Moreover, we investigate the influence of atmospheric turbulence, the signal-to-noise ratio (SNR) of eavesdropping links, and shadowing conditions on the considered system.
This paper constructs a radio frequency (RF)/free space optical (FSO) system for the hybrid satellite-terrestrial relay network (HSTRN), which applies the decode and forward protocol. The shadowed Rician (SR) and Gamma-Gamma (GG) distribution are used to portray the fading of RF and FSO links. The secrecy outage probability (SOP) of the HSTRN system is calculated in this paper. We deduce the closed-form expression of SOP. Moreover, we investigate the influence of atmospheric turbulence, the signal-to-noise ratio (SNR) of eavesdropping links, and shadowing conditions on the considered system.
In this paper, the secrecy performance of a mixed free space optical (FSO)/radio frequency (RF) integrated satellite-high altitude platform (HAP) relaying networks for terrestrial multiusers with the existence of an eavesdropper is investigated. In this network, FSO is adopted to establish the link between the satellite and HAP for which it experiences Gamma-Gamma distributions under different detection schemes (i.e., heterodyne and intensity modulation direct detection). The transmission between the amplify-and-forward (AF) relaying HAP and terrestrial multiusers is through the RF and is modeled as shadowed-Rician fading distribution. Owning to broadcasting nature of RF link, it is assumed that an eavesdropper attempts to intercept the users’ confidential message, and the eavesdropper link is subjected to Rician distributions. Specifically, the closed-form expression for the system equivalent end-to-end cumulative distribution function is derived by exploiting the Meijer’s G and Fox’s H functions. Based on this expression, the exact closed-form expressions of the system connection outage probability, secrecy outage probability, and strictly positive secrecy capacity are obtained under the different detection schemes at HAP. Moreover, the asymptotic analyze of the system secrecy outage probability is provided to obtain more physical insights. Furthermore, the accuracy of all the derived analytical closed-form expressions is verified through the Monte-Carlo simulations. In addition, the impact of atmospheric turbulence, pointing errors, shadowing severity parameters, and Rician factor are thoroughly evaluated. Under the same system conditions, the results depict that heterodyne detection outperforms the intensity modulation direct detection.
In this paper, we study the physical layer secrecy performance of a hybrid satellite and free-space optical (FSO) cooperative system. The satellite links are assumed to follow the shadowed-Rician fading distribution, and the channel of the terrestrial link between the relay and destination is assumed to experience the gamma-gamma fading. For the FSO communications, the effects of different types of detection techniques (i.e., heterodyne detection and intensity modulation with direct detection) as well as the pointing error are considered. We derive exact analytical expressions for the average secrecy capacity and secrecy outage probability (SOP) for both cases of amplify-and-forward (AF) and decode-and-forward (DF) relaying. The asymptotic analysis for the SOP is also conducted to provide more insights on the impact of FSO and satellite channels on secrecy performance. It is found that with the AF with fixed gain scheme, the secrecy diversity order of the investigated system is only dependent on the channel characteristics of the FSO link and the FSO detection type, whereas the secrecy diversity is zero when the relay node employs DF or AF with variable-gain schemes.
This work investigates the physical layer secrecy of a multi-antenna hybrid satellite-terrestrial relay networks (HSTRN) with jamming, in which a satellite aims to make communication with a destination user by means of a relay, along with spatially random eavesdroppers.In order to weaken the signals of eavesdroppers, the conventional relay can also generate intentional interference, besides forwarding the received signal.Shadowed-Rician fading is adopted in satellite link, while Rayleigh fading is adopted in terrestrial link, eavesdropper link and jamming link.The analytical and asymptotic formulas for the system secrecy outage probability (SOP) are characterized.Practical insights on the diversity order of the network are revealed according to the asymptotic behavior of SOP at high signal-to-noise ratio (SNR) regime.Then, analysis of the system throughput is examined to assess the secrecy performance.In the end, numerical simulation results are presented to validate the theoretical analysis and point out: (1) The secrecy performance of the considered network is affected by the channel fading scenario, the system configuration; (2) Decrease of the relay coverage airspace can provide better SOP performance; (3) Jamming from the relay can improve secrecy performance without additional network resources.
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.
This paper addresses the secure transmission problem of an integrated satellite-terrestrial relay networks (ISTRN), where multiple malicious eavesdroppers attempt to overhear the confidential signals from the satellite to a terrestrial user. Here, the relay is employed with multiple antenna and the decode-and-forward protocol is used. By supposing that the perfect instantaneous channel state information (CSI) of satellite-relay link and the statistical CSI of relay-user and relay-eavesdropper links are available at the relay, an optimization problem is first formulated to maximize the secrecy rate of the ISTRN. Then, the secure transmission scheme is designed to solve the optimization problem and obtain the closed-form beamforming weight vector. To further insight the secrecy performance of the proposed scheme, we derive the analytical expressions of the secrecy outage probability (SOP) of the considered ISTRN, where the satellite-relay link undergoes the shadowed-Rician fading, and the links of relay to user as well as eavesdroppers undergo the correlated Rayleigh fading. Finally, numerical results are given to confirm the superiority of the proposed scheme and the validity of the SOP analysis.
We analyze the secrecy outage probability of a dual-hop radio frequency (RF)-free space optical (FSO) transmission systems. We assume that the eavesdropping occurs at the RF channel which experiences Nakagami-m fading while the FSO link suffers from Málaga turbulence-induced fading. More precisely, we derive an analytical expression for the lower bound of secrecy outage probability (SOP) to study the secrecy performance of dual-hop RF-FSO transmission system with the fixed-gain amplify-and-forward relaying protocol.