Design and implementation of LED-LED indoor visible light communication system

摘要： This paper investigates the experimental performance of LEDs as both photo-emitter and photoreceiver. In this work LED-LED link is established using BJT and MOSFET based drive circuits at transmitting side and resistor driver operated in photo-conductive mode is used at the receiver side. The LED response as transmitter and receiver is investigated at different operating frequencies with the distance of up to 20 cm and the data rate of 1 Mbps. The SNR values of 8 dB and 11 dB are obtained using BJT and MOSFET drivers respectively at a distance of 20 cm. Furthermore, six different color LEDs are tested on both sides of transceiver to determine the best performing pair. It is observed that the red color LEDs have good responses as a photodiode due to its long wavelength in the visible spectrum. However their performance is significantly effected by ambient noise. Moreover, the responsivity of the Red color LED operated as photoreceiver with respect to different biasing voltages is also experimentally measured and discussed.