Performance evaluation of Digital Colour Shift Keying for visible light communications

In this paper, multilevel Digital Colour Shift Keying (DCSK) and DCSK using multi-colour LEDs are considered. Moreover, to increase the spectral efficiency of DCSK, Spatial Colour Shift Keying (SCSK) is proposed, in which DCSK is combined with Space Shift Keying. The symbol error rate of DCSK and SCSK performances are evaluated from theoretical analysis and simulation analysis, under consideration of the transmitter-receiver configuration within the room. Consequently, when the channel gain ratio is smaller than 1.7, the energy efficiency of DCSK is better than those of SCSK and Generalised Space Shift Keying (GSSK), on the other hand, SCSK is improved when the channel gain ratio becomes large. Moreover, when the number of transmitters is large, the spectral efficiency of SCSK can be improved compared with DCSK.