VLC-IR Dual Switching Transmission System for VLC Sensor Networks

In this paper, we study the dual transmission technique which uses visible light communication and IR in visible light communication IoT system. Conventional visible light communication has a problem that the communication is disconnected when visible light does not reach directly or when a shadow region occurs due to an obstacle. In addition, visible light communication provides illumination together. The disadvantage is that the communication can no longer be provided when the lighting needs to be turned off. In order to solve this problem, we overcome the limitations of visible light communication by dual transmission using IR. Actively switches LEDs and IRs in an environment that considers the reception power attenuation and shadowing according to the reception distance. In addition, the low speed communication function can be provided through IR transmission mode when the lighting needs to be turned off. In a typical LOS transmission environment, we analyze the received power of an RGB channel that depends on the RGB mixing ratio of the LED. Since the performance of the RGB channel depends on the light emission color of the LEDs, the worst channel is compensated by dual transmission with IR mode. We propose a technique to improve the performance of the entire system by diversity scheme through dual transmission.