In this article, we determine the secrecy performance of a dual-hop hybrid free space optics (FSO)-visible light communication (VLC) system with a randomly located legitimate Internet of Things (IoT)-based receiver in the presence of two distinct eavesdroppers (EDs). We consider one FSO-based ED located near the relay, wiretapping the FSO link. However, another ED wiretaps the information from the multiple VLC sources embedded on the ceiling of the room. We consider the three different scenarios for VLC-based ED: 1) the effect of uniformly distributed ED in the absence of any secured zone in the VLC coverage area; 2) the impact of uniformly distributed ED in the presence of VLC secured area; and 3) the effect of random waypoint (RWP) distributed ED on the system’s security. The secrecy performance of the system is evaluated based on known and unknown instantaneous channel state information (CSI) of EDs. Furthermore, the closed form expression for secrecy outage probability (SOP) in terms of Meijer’s-G and Gauss hypergeometric functions is derived. In order to have a better insight into the system’s performance, analytical results are expressed asymptotically in the high signal-to-noise ratio (SNR) regime. Following that, Monte Carlo simulations are done to validate the theoretical results. Additionally, a secrecy threshold is obtained in order to comprehend the system’s security and reliability.
In this article, we determine the secrecy performance of a dual-hop hybrid free space optics (FSO)-visible light communication (VLC) system with a randomly located legitimate Internet of Things (IoT)-based receiver in the presence of two distinct eavesdroppers (EDs). We consider one FSO-based ED located near the relay, wiretapping the FSO link. However, another ED wiretaps the information from the multiple VLC sources embedded on the ceiling of the room. We consider the three different scenarios for VLC-based ED: 1) the effect of uniformly distributed ED in the absence of any secured zone in the VLC coverage area; 2) the impact of uniformly distributed ED in the presence of VLC secured area; and 3) the effect of random waypoint (RWP) distributed ED on the system’s security. The secrecy performance of the system is evaluated based on known and unknown instantaneous channel state information (CSI) of EDs. Furthermore, the closed form expression for secrecy outage probability (SOP) in terms of Meijer’s-G and Gauss hypergeometric functions is derived. In order to have a better insight into the system’s performance, analytical results are expressed asymptotically in the high signal-to-noise ratio (SNR) regime. Following that, Monte Carlo simulations are done to validate the theoretical results. Additionally, a secrecy threshold is obtained in order to comprehend the system’s security and reliability.
In this article, the secrecy performance of a hybrid radio frequency (RF)/visible light communication (VLC) system is studied. In this hybrid system, the source node (i.e., Alice) transmits information to the relay node via the outdoor RF link. Nakagami-m fading and path loss are considered for the RF link. The relay node includes an outdoor component and an indoor component, which are connected by using a wired medium. The outdoor component receives and recovers information by using the decode-and-forward (DF) relaying scheme and then transmits it to the indoor component. The indoor component then converts the received electrical signal into an optical signal by using a light-emitting diode. A legitimate receiver (i.e., Bob) deployed on the floor receives the optical signal. An eavesdropper (i.e., Eve) deployed in the RF or VLC link wiretaps the confidential information. In this study, we use the secrecy outage probability (SOP) and the probability of strictly positive secrecy capacity (SPSC) to evaluate the system performance. We then obtain the closed-form expression for a lower bound on the SOP and an exact closed-form expression for the probability of SPSC when the RF and VLC links are wiretapped, respectively. Numerical results are presented to validate the accuracy of our derivations. We further discuss the effects of the noise standard deviation, the equivalent threshold of the signal-to-noise ratio, and the floor radius on the system secrecy performance when the VLC link is eavesdropped upon. For the case when the RF link is eavesdropped upon, the impacts of the distance between Alice and the relay, the path loss exponent, the fading factor, and the distance between Alice and Eve on secrecy performance are also provided.
Over recent years, visible light communications (VLC) has gained prominence as a promising alternative to traditional RF communication, offering advantages in terms of bandwidth and security. This paper investigates the physical-layer security for a practical indoor VLC system where the positions of a legitimate receiver (Bob) and an eavesdropper (Eve) are considered to be random within their circular receiving planes. For this system model, the statistics of the VLC channel gains are obtained using which, closed-form expressions for the secrecy outage probability are derived. The analytical results, validated through Monte Carlo simulations, demonstrate the impact of key system parameters, namely signal-to-noise ratio, Bob and Eve relative positions, and the target secrecy rate on the SOP performance.
This letter investigates the secrecy performance in visible light communication (VLC) in the presence of randomly located colluding eavesdroppers (EDs). Colluding EDs can combine their observations and degrade the secrecy performance of the VLC systems. Utilizing the numerical inversion of a characteristic function, the probability distribution of the combined signal-to-noise ratio of colluding EDs is analyzed. The closed-form expression of the secrecy outage probability is derived and verified by Monte Carlo simulations.
Abstract This paper investigates the physical layer security of indoor visible light communication (VLC) systems in the presence of randomly located eavesdroppers using a stochastic geometry framework. Unlike traditional LOS-only or perfect-CSI assumptions, this work incorporates a more realistic setting where the eavesdropper’s channel state information (CSI) is unknown, and both line-of-sight (LOS) and first-order non-line-of-sight (NLOS) reflections are accounted for in the channel modelling. The analysis further integrates device orientation randomness and evaluates security under eavesdroppers employing selection combining (SC) and maximum ratio combining (MRC). Closed-form expressions for the channel gain, SNR distribution, and secrecy outage probability (SOP) are derived by exploiting the spatial statistics of a bounded Poisson point process (PPP). Results show that incorporating NLOS components significantly enhances legitimate SNR and improves secrecy performance, while eavesdropper collaboration using maximum ratio combining presents the worst-case security threat. Monte Carlo simulations validate the analytical derivations, demonstrating close agreement across various system parameters. The study offers an accurate and practical secrecy analysis framework for next-generation VLC deployments in realistic indoor environments.
Abstract In this paper, we investigate the secrecy performance of a dual-hop hybrid radio frequency–visible light communication (RF–VLC) system in which we consider a single source antenna ( S ) transmitting data signals via RF channel through decode and forward (DF) relay ( R ) toward an authorized receiving antenna ( D ) at the destination via VLC channel. In this system, we assume that the eavesdropper ( E ) attempts to eavesdrop the RF channel ( S , R ) during transmission of the signal. The relay decodes the incoming RF signal into corresponding optical signal and retransmits toward destination via VLC channel ( R , D ). The RF and VLC channels of the hybrid system are modelled using generalized-K fading distribution and generalized Lambertian radiant intensity distribution respectively. Also the receiver is assumed to be mobile and its mobility is defined by random waypoint (RWP) model. The channels statistics are used to derive the exact analytical expressions for average secrecy capacity and intercept probability in terms of Meijer’s G-function. The derived closed form analytical expressions are the efficient tool to illustrate the impact of variation in different channel parameters on the secrecy performance, namely, shadowing parameters of RF channel, field of view (FOV), semiangle, and the order of Lambertian emission of the VLC channel. Further, numerical analysis is carried out to support the mathematical analysis of the RF–VLC hybrid system.
This article investigates the physical-layer security for a random indoor visible light communication (VLC) network with imperfect channel state information (CSI) and a protected zone. The VLC network consists of three nodes, i.e., a transmitter (Alice), a legitimate receiver (Bob), and an eavesdropper (Eve). Alice is fixed in the center of the ceiling, and the emitted signal at Alice satisfies the nonnegativity and the dimmable average optical intensity constraint. Bob and Eve are randomly deployed on the receiver plane. By employing the protected zone and considering the imperfect CSI, the stochastic characteristics of the channel gains for both the main and the eavesdropping channels is first analyzed. After that, the closed-form expressions of the average secrecy capacity and the lower bound of secrecy outage probability are derived, respectively. Finally, Monte Carlo simulations are provided to verify the accuracy of the derived theoretical expressions. Moreover, the impacts of the nominal optical intensity, the dimming target, the protected zone, and the imperfect CSI on secrecy performance are discussed, respectively.