Visible light communication (VLC) is a burgeoning field in wireless communications as it considers illumination and communication simultaneously. The broadcast nature of VLC makes it necessary to consider the security of underlying transmissions. A physical-layer security (PLS) scheme by introducing jamming LEDs is considered in this paper. The secrecy rate of an indoor VLC system with multiple LEDs, one legitimate receiver, and multiple eavesdroppers is investigated. Three distributions of input signal are assumed, i.e., truncated generalized normal distribution (TGN), uniform distribution, and exponential distribution. The results show that jamming can improve the secrecy performance efficiently. This paper also demonstrates that when the numbers of LEDs transmitting information-bearing signal and jamming signal are equal, the average secrecy rate can be maximized.
Visible light communication (VLC) is a burgeoning field in wireless communications as it considers illumination and communication simultaneously. The broadcast nature of VLC makes it necessary to consider the security of underlying transmissions. A physical-layer security (PLS) scheme by introducing jamming LEDs is considered in this paper. The secrecy rate of an indoor VLC system with multiple LEDs, one legitimate receiver, and multiple eavesdroppers is investigated. Three distributions of input signal are assumed, i.e., truncated generalized normal distribution (TGN), uniform distribution, and exponential distribution. The results show that jamming can improve the secrecy performance efficiently. This paper also demonstrates that when the numbers of LEDs transmitting information-bearing signal and jamming signal are equal, the average secrecy rate can be maximized.
Despite offering higher security than radio frequency (RF) channels, the broadcast nature of the visible light communication (VLC) channel makes VLC links inherently susceptible to eavesdropping by unauthorized users. In this work, we consider the physical-layer security of VLC links aided by friendly jamming. The jammer has multiple light sources, but does not have access to the data transmitted. The eavesdropper's reception is degraded by a jamming signal that causes no interference to the legitimate receiver. Due to the limited dynamic range of typical light-emitting diodes (LEDs), both the data and jamming signals are subject to amplitude constraints. Therefore, we begin with deriving a closed-form secrecy rate expression for the corresponding wiretap channel, and adopt secrecy rate as the performance measure. Then, we formulate a linear programming problem to maximize the secrecy rate when the eavesdropper's channel is accurately known to the jammer. Finally, we consider robust beamforming to maximize the worst-case secrecy rate when information about the eavesdropper's channel is uncertain due to location uncertainty. The robust scheme makes use of simple linear programming, making real-time implementation feasible in a variety of real-world scenarios.
Visible light communication (VLC) is a new enabling communication technology that exploits illumination devices, mostly high-brightness light-emitting diodes (LEDs), to establish high-speed short-range wireless communication links. VLC is a promising technology that has gained significant interest in the last decade due to its high data rates and low cost of deployment. Although VLC systems are less susceptible to eavesdropping than RF systems since light does not penetrate through walls, they become as vulnerable as their radio-frequency (RF) counterparts when their nodes are deployed in public areas and/or when there are large windows. Thus, security for VLC systems is as important as it is for RF systems. Security in wireless communication systems may be enhanced by introducing physical layer security (PLS) techniques. In fact, PLS has been applied to a wide range of RF applications in an effort to improve the overall security by complementing existing cryptography-based security techniques. The potential of PLS stems from its ability of leveraging features of the surrounding environments via sophisticated encoding techniques at the physical layer. Indeed, PLS schemes can be applied in the same spirit to VLC systems. \n \nThere exist many specificities that characterize VLC systems, leading to major differences compared to RF systems. Specifically, VLC channels are quasi-static and real valued channels, which seemingly simplify the application of PLS techniques. However, due to the limited dynamic range of the LEDs, VLC systems impose an amplitude constraint on the channel input, which makes unbounded inputs not admissible. As a result, the performance of PLS schemes must be revised in the VLC context due to its different operating constraints. \n \nWe propose in this thesis enhancing the secrecy performance of VLC systems through PLS techniques. Firstly, we consider the degraded single-input single-output (SISO) VLC system. We derive achievable secrecy rates using continuous and discrete input distributions and we demonstrate the substantial improvement in the secrecy performance by using discrete distributions. Secondly, we consider the multiple-input single-output (MISO) VLC systems. We consider at first the case of randomly located eavesdroppers, in which we develop an associated achievable secrecy rate and we develop a beamforming-based precoding scheme that enhances the secrecy performance of this class of systems. In the second part, we consider the multi-user (MU) MISO broadcast system with confidential messages and we develop linear precoding schemes that enhance typical secrecy performance measures, including the max-min fairness and the weighted fairness. Finally, we consider the multiple-input multiple-output (MIMO) VLC system. We derive achievable secrecy rates using continuous and discrete distributions and we develop linear precoding schemes that improve its secrecy performance.
Recently, the physical layer security (PLS) is becoming an important research area for visible light communication (VLC) systems. In this paper, the secrecy rate performance is investigated for an indoor multi-user visible light communication (VLC) system using artificial noise (AN). In the considered model, all users simultaneously communicate with the legitimate receiver under wiretap channels. The legitimate receiver uses the minimum mean squared error (MMSE) equalizer to detect the received signals. Both lower bound and upper bound of the secrecy rate are obtained for the case that users' signals are uniformly distributed. Simulation results verify the theoretical findings and show the system secrecy rate performance for various positions of illegal eavesdropper.
Summary Visible light communication (VLC) is considered to be a great replacement or complement to existing radio frequency networks to provide the future fifth‐generation (5G) wireless technology with higher data rates for indoor connectivity, which alleviates the traffic demand. Therefore, many issues emerged regarding the security in 5G networks as human safety is at risk. This work presents a comprehensive study on the physical‐layer security (PLS) and solutions in 5G networks, specifically, the security of VLC technology as one of the core PLS solutions for 5G future wireless networks. Furthermore, VLC threats and PLS solutions are extensively investigated. Based on our study, we propose a new indoor VLC secure model to enhance the secrecy performance in VLC networks using a combination of multiple PLS techniques to achieve this aim as beamforming, secure communication zones, and friendly jamming. The simulation results with respect to the received optical power and signal‐to‐noise ratio (SNR) prove that the proposed indoor VLC model can improve the secrecy performance. As the user's SNR exceeded 100 dB and optical received power reached 15 mW, the malicious user's SNR barely reached 30 dB with a 4‐μW received power outside the target zone increasing his interference level. Finally, future research directions in VLC security are outlined to encourage future research.
In this paper, we address the secure data transmission through visible light communication (VLC) using physical layer security (PLS) techniques and particularly, optical beamforming with the zero-forcing algorithm. More precisely, we consider the secrecy capacity of classical multiple-input single-output VLC so that the system can deal with eavesdroppers by minimizing the secrecy outage probability (SOP). The considered wireless channel is modeled by the Gaussian distribution, which is subject to amplitude constraints. We quantity the achievable secrecy capacity and SOP for the conventional line-of-sight VLC link and show that how the beamforming can determine the optimal placement of the transmitters. We also show that for a given SOP, the proposed optimal placement offers a signal-to-noise ratio gain of up to 6 dB compared to classical methods such as uniform placement of the transmitters. Our numerical results indicate that the proposed optimal LED arrangement can achieve an SOP of 10−10 while the SOP with uniform arrangement is equal to 10−4.
This paper considers improving the confidentiality of visible light communication (VLC) links within the framework of physical-layer security. We study a VLC scenario with one transmitter, one legitimate receiver, and one eavesdropper. The transmitter has multiple light sources, while the legitimate and unauthorized receivers have a single photodetector, each. We characterize secrecy rates achievable via transmit beamforming over the multiple-input, single-output (MISO) VLC wiretap channel. For VLC systems, intensity modulation (IM) via light-emitting diodes (LEDs) is the most practical transmission scheme. Because of the limited dynamic range of typical LEDs, the modulating signal must satisfy certain amplitude constraints. Hence, we begin with deriving lower and upper bounds on the secrecy capacity of the scalar Gaussian wiretap channel subject to amplitude constraints. Then, we utilize beamforming to obtain a closed-form secrecy rate expression for the MISO wiretap channel. Finally, we propose a robust beamforming scheme to consider the scenario wherein information about the eavesdropper's channel is imperfect due to location uncertainty. A typical application of the proposed scheme is to secure the communication link when the eavesdropper is expected to exist within a specified area. The performance is measured in terms of the worst-case secrecy rate guaranteed under all admissible realizations of the eavesdropper's channel.