Biblio

Visible light communication (VLC) is an important alternative and/or complementary technology for next generation indoor wireless broadband communication systems. In order to ensure data security for VLC in public areas, many studies in literature consider physical layer security (PLS). These studies generally neglect the reflections in the VLC channel and assume no inter symbol interference (ISI). However, increasing the data transmission rate causes ISI. In addition, even if the power of the reflections is small compared to the line of sight (LoS) components, it can affect the secrecy rate in a typical indoor VLC system. In this study, we investigate the effects of ISI and reflected channel components on secrecy rate in multiple-input single-output (MISO) VLC scenario utilized null-steering (NS) and artificial noise (AN) PLS techniques.

A conventional visible light communication system consists of a transmitter, a jammer that includes a few light emitting diodes, a legal listener and an eavesdropper. In this work, a similar system is designed with a collimating lens in order to create an extra layer of practical physical security measure. The use of a collimating lens makes it available to spatially limiting data transmission to an area under the lensed transmitter. Also focused data transmission through the optical lens, increases the secrecy rate. To investigate the applicability of the proposed design we designed a sample experimental setup using USRP and implemented in a laboratory environment. In the proposed set up, the receiver is in a fixed position. However, it is possible to implement an easy, practical and cheap hardware solution with respect to a beamforming type VLC that uses directional beam forming method to establish transmission to a dynamic target. In addition, it is achievable to control the size of the area where a receiver can access data by manipulating the distance between the optical lens and transmitter.

Visible light communication (VLC) is a promising technique in the fifth and beyond wireless communication networks. In this paper, a secure multiple-input single-output VLC network is studied, where simultaneous lightwave information and power transfer (SLIPT) is exploited to support energy-limited devices taking into account a practical non-linear energy harvesting model. Specifically, the optimal beamforming design problems for minimizing transmit power and maximizing the minimum secrecy rate are studied under the imperfect channel state information (CSI). S-Procedure and a bisection search is applied to tackle challenging non-convex problems and to obtain efficient resource allocation algorithm. It is proved that optimal beamforming schemes can be obtained. It is found that there is a non-trivial trade-off between the average harvested power and the minimum secrecy rate. Moreover, we show that the quality of CSI has a significant impact on achievable performance.