Physical-layer security for indoor visible light communications

This paper considers secure transmission over the visible light communication (VLC) channel by the means of physical-layer security techniques. In particular, we consider achievable secrecy rates of the multiple-input, single-output (MISO) wiretap VLC channel. The VLC channel is modeled as a deterministic and real-valued Gaussian channel subject to amplitude constraints. We utilize null-steering and artificial noise strategies to achieve positive secrecy rates when the eavesdropper´s channel state information (CSI) is perfectly known and entirely unknown to the transmitter, respectively. In both scenarios, the legitimate receiver´s CSI is available to the transmitter. We numerically evaluate achievable secrecy rates under typical VLC scenarios and show that simple precoding techniques can significantly improve the confidentiality of VLC links.