Cyclic mapping method for digital color shift keying with RGB-LED array

Digital color shift keying (DCSK) is a visible light communication (VLC) intensity modulation method, which can fulfill the both roles of lighting and communication. DCSK transmits data through an intensity ratio of red, green, and blue (RGB), which can be represented by digital “on-off” LED control by multiple RGB-LEDs (i.e., RGB-LED array). Moreover, a perceived color on human eye (i.e., target color) of modulated optical signal can be shifted by M constellation points for M-ary DCSK. However, color deviation over RGB-LED array face is caused by a fixed mapping of lighted LEDs corresponding to each DCSK symbol. In this paper, we consider cyclic mapping method for the target color controlled DCSK system to mitigate the color deviation of RGB-LED array face. Moreover, we experimentally evaluate the DCSK light signal by correlated color temperature (CCT) and error vector magnitude (EVM) performance. As a result, the CCT performance of DCSK system with cyclic mapping can be improved when the desired CCT of the target color is 3000K, 4000K, or 5700K. While, the DCSK system with cyclic mapping method can achieve similar EVM performance of the conventional DCSK system.