Space-domain dimming control scheme based on SCFDM for visible light communications

In this paper, a space-domain dimming control scheme based on single-carrier frequency-division multiplexing (SD-SCFDM) is proposed for visible light communications (VLC). The SD-SCFDM scheme not only has the advantage of additional spatial dimming domain but inherits the strengths of SCFDM in resisting the clipping distortion and high-frequency attenuation, which can support the efficient communication under different illumination requirements. Considering the limited dynamic range of light emitting diode (LED) and bandwidth limitation in VLC system comprehensively, SD-SCFDM can achieve the communication with spectral efficiency of at least 1 bit/s/Hz higher than SD scheme based on orthogonal frequency-division multiplexing (SD-OFDM) in the whole dimming range. Additionally, the proposed SD-SCFDM has the low computational complexity of encoding. Meanwhile, for the proposed scheme with spectral efficiency of 2.5, 3 and 3.5 bit/s/Hz, the required number of LED chips in one lamp can be reduced by about 55.9%, 50% and 59% compared with its OFDM-based counterparts, respectively. In conclusion, the SD-SCFDM scheme shows the great potential and feasibility for future practical implementations of VLC.