3-Gb/s Visible Light Communication over 5 m Distance Based on Imaging System with Low Transmission Power and Off-the-Shelf LEDs

We demonstrate indoor parallel visible light communication (VLC) achieving 3 Gb/s date rate under distance 5 meters with transmission power 15.9 mW, 189.1 mW and 63.4 mW for red, green and blue LEDs, respectively. The original bandwidths for the adopted LEDs are approximately 10 MHz. A lens is employed at the transmitter side to concentrate the light. Due to the 5-meter distance, different single-color LEDs exhibit separated light spots at the receiver side, which creates parallel transmission paths with negligible inter-color interference. Analogue pre-equalization is adopted to extend the 3-dB bandwidth to approximately 300 MHz, and Volterra series-based digital post-equalizer is adopted to mitigate the nonlinearity and residue inter-symbol interference. In the experiments, on-off keying modulation is adopted due to low reception power at 5-meter distance, and the symbol rate of 1 G per second is adopted for each single-color LED. It is demonstrated that inter-color signal-interference ratio is above 20 dB, and the residue bit error rates of 1.82 x 10(-4), 1.4 x 10(-3) and 1.3 x 10(-3) are achieved by red, green and blue LEDs, respectively, all below threshold 3.8 x 10(-3) for standard forward error correcting code with 7% redundancy.