Experimental Demonstration of Text and Audio Transmission over Single Channel and Relay Assisted VLC Systems

There is an increasing need for high data rate and massive connectivity requirements in the Internet of Things (IoT) based communication applications. Therefore, visible light communications (VLC) have become a popular area of research for both academia and industry. This is due to wide bandwidth, license-free spectrum, energy efficiency, and low implementation cost of VLC. In addition, traditional radio frequency (RF) based communications face issues with spectral congestion. In this paper, we develop an experimental setup of VLC based data transmission and reception. We demonstrate text and audio transmission over a single VLC link of upto 2 m using light emitting diode (LED) and collimating lens as the transmitter and receiving lens with a PIN photodetector as receiver. VLC system's link length improved up to 4m with an amplify-and-forward (AF) relay for data transmission and reception. Further, it is presented that with 4 LEDs, the distance for error-free transmission for text data increased from 50 cm to 180 cm. Useful insights into the VLC systems performance are obtained through the experimental measurements of the received power for various link lengths, receiver angular position with respect to the transmitter, and the number of the transmitting white LEDs used.