Novel Dimmable Visible Light Communication Approach Based on Hybrid LACO-OFDM

In this paper, a dimming control approach is proposed for visible light communication based on layered asymmetrically clipped optical orthogonal frequency-division multiplexing (LACO-OFDM) to satisfy different illuminative requirements. The proposed scheme combines LACO-OFDM and negative LACO-OFDM (NLACO-OFDM), which is first introduced to the best of our knowledge. The proportion of the two signals is variable to achieve the desired luminance. The dynamic range is fully exploited by both LACO-OFDM and NLACO-OFDM, resulting in high spectral efficiency. The achievable rate and optimal power allocation are introduced in this paper. Moreover, the achievable rate that varies with the layer number and noise power is also investigated. Simulation results show that the performance of the proposed approach is superior to that of the previous LACO-OFDM-based scheme in terms of power and spectral efficiencies. Meanwhile, the selection of the layer number is dependent on the desired dimming level and noise environment.