Real-Valued Precoding-Enabled ACHO-FBMC for Band-Limited Visible Light Communications

The filter bank multi-carrier (FBMC) enabled visible light communication (VLC) systems based on the well-designed prototype filter with excellent time-frequency focusing characteristics, exhibit higher spectral efficiency and lower out-of-band spectral leakage than orthogonal frequency-division multiplexing. Asymmetrical clipping-aided hybrid optical FBMC (ACHO-FBMC) is a spectral- and power-efficient modulation scheme for VLC systems. However, the ACHO-FBMC cannot avoid the high signal peak-to-average power ratio (PAPR) problem and suffers power fading induced by limited modulation bandwidth. In this letter, we propose a real-valued precoded ACHO-FBMC modulation scheme to reduce signal PAPR and equalize subcarrier signal-to-noise ratio (SNR) so as to improve transmission performance. The simulation results revealed that the precoding techniques can reduce signal PAPR up to 4.7 dB at the complementary cumulative distribution function of 1e-4. Besides, the transmission performance of the 1.21-Gbps precoded FBMC signals was experimentally investigated in a blue light emitting diode-based VLC system with a 1-m wireless link. It indicated that the subcarrier SNR was well equalized with the proposed precoding techniques. Moreover, the bit error rate was reduced by about an order of magnitude.