Transmitter for 1.9 Gbps phosphor white light visible light communication without a blue filter based on OOK-NRZ modulation

Due to narrow bandwidth and slow yellow light, it is difficult for visible light communication (VLC) systems based on high-power phosphor-coated light-emitting diodes (LEDs) to support high data rates. In this paper, a novel transmitter based on a commercial phosphor-coated LED is proposed, which can achieve a wideband VLC system without a blue filter. The transmitter consists of a folded equalization circuit and a bridge-T equalizer. The folded equalization circuit is based on a new equalization scheme and can expand the bandwidth of high-power LEDs more significantly. The bridge-T equalizer is used to reduce the influence of the slow yellow light generated by the phosphor-coated LED, which is more suitable than blue filters. Utilizing the proposed transmitter, the 3 dB bandwidth of the VLC system using the phosphor-coated LED is extended from several megahertz to 893 MHz. As a result, the VLC system can support real-time on-off keying non-return to zero (OOK-NRZ) data rates up to 1.9 Gb/s at a distance of 7 m with a bit error rate (BER) of 3 x 10-5.