| Title |
Visible Light Communication System with LEDs using Digital Dimming Scheme |
| Authors |
김혜수(Hea-Su Kim) ; 염정덕(Jeongduk Ryeom) |
| DOI |
https://doi.org/10.5370/KIEE.2019.68.10.1230 |
| Keywords |
Dimmable LED; dimming; lighting; visible light communication; telemetry system |
| Abstract |
Depending on the conditions of the transmission data; the luminous flux changes in the visible light communication(VLC) system using light emitting diode(LED)s. Therefore; it is difficult to properly implement the lighting environment required by users; because of flicker or difficulty in maintaining the proper level of dimming. In this study; we proposed a new digital dimming technology using white LEDs to compensate for the increasing level of dimming caused by luminous flux of LEDs for data transmission; so that it can maintain the constant level of dimming. And we developed a VLC system using this technology. In the proposed digital dimming technology; the dimming level of dimmable LEDs and the variation in dimming level caused by the LEDs for data transmission are converted into binary values. Hence a new dimming level is created from their differences. The fluctuation of the dimming level due to the transmitted data signals is adjusted real-time in this technology. The dimmable LEDs and data LEDs are operated independently in the developed VLC system. In addition; by using bidirectional communication with LEDs for request signals; the transmitter and the receiver are synchronized easily and the multiple data transmission is possible. In order to verify the validity of this technology; we carried out the experiments to measure temperature by the sensor and transmit the measured temperature data using the developed system. From experimental results; rates of dimming variation of less than 2% have been achieved in every dimming level of over 10% using this technology. and the VLC system enabled telemetry for temperatures from ?55°C to 125°C. |