Design and implementation of a bi-directional visible light communication system

High power Light Emitting Diodes (LED) are increasingly used for indoor illumination due to energy efficiency and high reliability. Moreover, LEDs inherent fast switching capability from the solid state electronics. Exploiting this capability we design and implement a bi-directional visible light communication (VLC) system which can be adopted to the LED illumination systems. High power LEDs are used for the downlink while infrared emitters are used for the uplink. Experiments under various environmental conditions show that the performance of the system largely depends on the distance between access point and user and the crosstalk between the transmitter and receiver. Therefore the crosstalk between the transmitter and receiver is mathematically modelled and experimentally evaluated to propose a crosstalk cancellation methodology.