Improved achievable secrecy rate of visible light communication with cooperative jamming

In this paper we study the problem of securing a visible light communication (VLC) link against passive eavesdropping, with the help of a (friendly) jammer. Differently from radio frequency (RF) communications, VLC imposes a peak amplitude constraint on the input distribution which renders Gaussian inputs not admissible. We provide an achievable secrecy rate that improves upon a recently established one in a concurrent work by Mostafa and Lampe. Our scheme follows from both the secrecy capacity result by Wyner and the artificial noise scheme by Goel and Negi, but using truncated Gaussian input distributions instead of uniform ones. Via numerical results, we show that our secrecy rate outperforms the concurrent rate in different settings.