In this paper, we consider an indoor environment where both visible light communication (VLC) and radio frequency (RF) networks are co-deployed. A source transmitter can use either a VLC-link or a RF-link to transmit the information to the legitimate user and we assume that an eavesdropper is also present to intercept the legitimate information transmission. Here, VLC network is considered as a primary network and RF network is used as a backup. Therefore, a source transmitter utilizes the RF-link only when VLC-link offers negative secrecy-rate for legitimate information transmission. In particular, we propose a secrecy-rate based secure link adaptation mechanism to select the RF-link. We derive the exact closed-form expressions for secrecy outage probability and system secrecy outage probability, and further, observe the effect of various physical parameters on security performance analysis.
This letter studies the security performance of hybrid radio frequency (RF) and visible light communication (VLC) system. 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 using the decode-and-forward (DF) relaying scheme. A legitimate receiver (Bob) arranged on the floor receives the optical signal. An eavesdropper (Eve) deployed in VLC link wiretaps the confidential information. In this paper, secrecy outage probability (SOP) is used to assess the performance of the system. We derive the closed expression of the lower bound of SOP when VLC link is wiretapped. Numerical results to validate the accuracy of our derivation.
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.
In this paper, a cooperative hybrid visible light communication (VLC)-radio frequency (RF) system with spatially random terminals is considered. Especially, a source node (
S) with a group of light-emitting diode (LED) lamps transmits information bits to a destination (
D), which is located out of
S’s coverage area, via a relay node (
R).
Ris equipped with a photodetector and an antenna to set up a VLC link between
Sand
R, and a radio frequency (RF) link between
Rand
D, respectively. Meanwhile, an eavesdropper (
E) equipped with a photodetector and an antenna tries to overhear the information delivery over VLC and RF links. Also, diversity receiving scheme is considered at
E, while the same modulation scheme is considered over both VLC and RF links. Furthermore, decode-and-forward scheme is adopted at
Rto process and forward the received VLC signals. By employing stochastic geometry, we first characterize the probability density function and cumulative distribution function of the received signal-to-noise-ratio over both VLC and RF links, while considering the randomness of the locations of both
R,
E, and
D. Then, the secrecy performance of the target system is studied by deriving the approximated expressions for the secrecy outage probability under various cases. Finally, the proposed analytical models are verified via Monte-Carlo simulations.
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.
Integrating visible light communication (VLC) and radio-frequency (RF) networks can improve the performance of communication systems in terms of coverage and data rates. However, adding RF links to VLC networks weakens the secrecy performance due to the broadcast and ubiquitous nature of RF links. This paper studies the physical layer security (PLS) in cooperative non-orthogonal multiple access (CoNOMA) hybrid VLC/RF systems. Consider a VLC system, where two entrusted users close to a VLC access point (AP) help an out-of-coverage legitimate user using RF signals in the presence of an eavesdropper. The AP transmits data to both entrusted users and the legitimate user using the principle of NOMA, where the entrusted users harvest energy from the received light intensity, decode the legitimate user's message, forward it using a RF link, and then decode their messages. It is required to maximize the secrecy rate at the legitimate user under quality-of-service (QoS) constraints using beamforming and DC-bias and power allocation. Different solutions are proposed for both active and passive eavesdropper cases, using semidefinite relaxation, zero-forcing, beamforming, and jamming. Numerical results compare between the different proposed approaches and show how the proposed approaches contribute in improving the secrecy performance of the proposed model.