Multilayered optical orthogonal frequency division multiplexing with offset quadrature amplitude modulation for visible light communication systems

A multilayered optical orthogonal frequency division multiplexing with offset quadrature amplitude modulation (LO-OFDM/OQAM) scheme is proposed for visible light communication (VLC) systems, which is inspired by the enhance optical OFDM/OQAM (EO-OFDM/OQAM) scheme. In this scheme, multiple layers of data are superimposed on the normal branch to further improve the spectral efficiency and power efficiency of the VLC systems. Specifically, the negative time-domain signals on each layer can be directly clipped as zeros without losing any information and demolishing the real-field orthogonal condition of the optical OFDM/OQAM system. Theoretical derivation is then given to prove the feasibility. Spectral efficiency, peak-to-average power ratio performance, bit error rate (BER) performance, and power efficiency of this proposed scheme are further investigated and compared with those of its counterparts. Simulation results show that the proposed LO-OFDM/OQAM scheme could achieve better BER performance in comparison with EO-OFDM/OQAM and DCO-OFDM/OQAM schemes, and at the same time, it is more power efficient. Our work would benefit the research and development of VLC systems.