Physical Layer Security Based on 2D Spatial Position Optimization of Relays in Reflected Indoor VLC System

A novel relay-aided physical layer security scheme is proposed in this letter. The channel model incorporates partial reflection components in the received signal according to the signal power. With this channel model, we formulate three security capacity maximization problems based on three relay-aided scenarios: cooperative jamming, decode-and-forward, and amplify-and-forward. By using an iterative algorithm, we jointly optimize the beamforming vector and two-dimensional spatial positions of relays based on the formulated problems to maximize the sum data rate while defending against eavesdropping. Numerical results show that the sum data rate for legal receivers can be improved by applying the proposed scheme.