VLC physical layer design based on Pulse Position Modulation (PPM) for stable illumination

Visible Light Communication (VLC) is promising new technology to be applied in the lighting system infrastructure. This communication function should not interfere with the existing lighting system. In order to prevent from this interference, the utilized modulation scheme should have a limited dynamic range to avoid flickering and dimming effect. We propose Pulse Position Modulation (PPM) technique in our VLC system due to its very minimum dynamic range feature. This paper describes the design and analysis of VLC physical layer using PPM scheme to obtain a stable illumination. The design of physical layer consists of analog front end (AFE) circuit and the data processing which is implemented in microcontroller and FPGA. Based on the test results of our VLC system using low cost photo detector, the system is able to provide stable illumination while reaching the maximum data transfer rate of 20 kbps.