The improvement of repeater system for Visible Light Communication

Visible Light Communication (VLC) Technology is the short range optical wireless communication technology using LEDs for communication and illumination. In this paper, we propose the improvement of the repeater system for visible light communication. Not just to extend the coverage, but also to transfer file and to increase the communication speed. Our proposed repeater system is composed of hardware and software components. The transmitter opens, splits, and sends a file with RS-232 serial communication interface. The byte data type is converted into light signal data type by using the on-off keying modulation (OOK) technique and is transmitted via LED. The repeater receives light signal data by photodiode then transmits it out again. With this method, light signal is amplified at each repeater. The receiver converts light signal data back into byte data and combines each set of bytes together, then the file can be saved by the user. This multi-hop communication gives more flexibility in communication because it helps to increase the distance between transmitter terminal and receiver terminal. Moreover, it also helps to avoid obstacle objects, such as walls, because VLC is a Line-of-Sight (LOS) technology. This system is improved from our previous system in terms of the number of sending character and the communication speed.