Dimming Control Systems Based on Low-PAPR SCFDM for Visible Light Communications

In this paper, the efficient dimming control systems based on single-carrier frequency-division multiplexing (SCFDM) are proposed for visible light communications (VLC). By virtue of the strengths of the low peak-to-average power ratio and the inherent resistance to high-frequency distortion, the proposed SCFDM-based dimming control schemes are adaptive to the bandwidth-limited and linearity-limited VLC system, thus supporting the wide dimming range for different illumination requirements. Two SCFDM-based VLC systems with dimming control including asymmetrical hybrid optical SCFDM (AHO-SCFDM) and DC-biased optical SCFDM (DCO-SCFDM) are proposed. For AHO-SCFDM with spectral efficiency of 1.75 bit/s/Hz and DCO-SCFDM with spectral efficiency of 2 bit/s/Hz, the 20<inline-formula> <tex-math notation="LaTeX">$\%$</tex-math></inline-formula> wider dimming range can be achieved than their orthogonal frequency-division multiplexing (OFDM) based counterparts, respectively. Meanwhile, the two proposed schemes can also achieve 24.8<inline-formula><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> and 31.3<inline-formula> <tex-math notation="LaTeX">$\%$</tex-math></inline-formula> gains of average spectral efficiency under the same dimming range compared with their counterparts, respectively. For an overall analysis, SCFDM shows the feasibility and superiority for dimming control systems.