Dimming Correction Scheme considering Luminous Characteristics of R, G, B LEDs in Visible Light Communication

Abstract

In visible light communication, it is difficult to control dimming of LED lamp or flicker occurs due to changes in luminous flux according to the data. In this paper, to solve this problem, we proposed a new correction scheme for dimming level in which the dimming level of an LED lamp is corrected in real time by considering the data transmission status. A non-linear correction scheme was applied for red and green LEDs because of the non-linear characteristics of the luminous flux according to the dimming level. Since the blue LED’s luminous flux can be assumed to be linear, a linear correction scheme using two-stage current was applied for blue LED in order to lower the minimum possible dimming level. A downscaled model of the visible light communication system was created to verify the validity of the proposed correction scheme for the dimming level. The luminous flux of red, green, and blue LEDs was also measured according to the dimming level. As a result, the dimming range of 9–100% was obtained regardless of the transmitted data condition. Also, transmitting the data of three sensors through red, green, and blue LEDs and constantly maintaining the entire lighting of the LED lamp are possible by applying the proposed dimming scheme.