Performance Enhancement Technique through Unequal Channel Allocation Algorithm in Visible Optical Communication

Abstract

Establishment and focus: Visible light communication system is a communication system that performs communication and lighting functions at the same time. Therefore, the transmission efficiency of communication and the brightness of lighting should be considered at the same time. LED devices have different colors of illumination light depending on the RGB mixing ratio. Depending on this blending ratio, the RGB channel state also changes. In addition, since visible light is used, instantaneous shadowing occurs when the visible light is blocked by an obstacle. In this paper, we propose an optimal channel allocation algorithm to maintain the optimal transmission rate according to the RGB channel condition that changes according to the LED mixing ratio, and to maintain the shadowing phenomenon and dimming level.
System: In this paper, we evaluate the channel condition according to the RGB mixing ratio of LED devices and assign different transmission methods for each channel. The worst channel among the RGB channels allocates and transmits the shadowing detection signal instead of the information data. Since this signal is transmitted continuously as a signal that is always on, instantaneous recognition is possible when the signal is interrupted, and the average dimming level is improved because it is always on. The best channel and the second channel are combined with each other to improve the data rate. In the LED device capable of color control and dimming control, it is difficult to maintain optimal performance of the entire system in the conventional fixed channel allocation method. By applying the proposed technique, it is possible to optimally allocate the channel to the changing RGB channel state and to cope with the shadowing phenomenon which is a problem of visible light communication. Also, since the worst channel is always on, dimming level can be improved and flicker can be prevented. This can improve the performance of the entire system. If the states of the three RGB channels are similar to each other, assigning the worst channel to the shadowing detection signal lowers the overall data rate. Further research on adaptive allocation schemes for these exceptional channel environments is needed.