Joint LED dimming and high capacity visible light communication by overlapping PPM

Piggybacking communication by illumination LEDs provides additional valuable functionality to LED lighting fixtures as optical communication transmitters at little cost. However, joint dimming control and high data-rate communication requires proper supporting protocols under the bandwidth limitation of LEDs. This paper applies overlapping pulse position modulation (OPPM) to achieve high capacity communication and flexible dimming. It then analyzes both illumination and communication performance in terms of dimming range, flicker severity index, cutoff data rate, and power and bandwidth efficiencies, all comparing against OOK and variable PPM modulation schemes. The results show the best performance using OPPM, making it an ideal candidate technology for emerging visible light communication.