Compensation of a VLC Phosphorescent White LED Nonlinearity by Means of Volterra DFE

In this letter, a visible light communication link is analyzed that employs a white phosphorescent light emitting diode (LED) as transmitter and a p-i-n photodiode combined with optical filter as receiver. Four- and eight-level pulse amplitude modulation is used for data transmission. The link is not only limited by a rather small bandwidth of ~20 MHz of the LED, but also its nonlinearity becomes a problem when the modulation index exceeds ~60%. It is shown that a receiver with a decision feedback equalizer (DFE) with nonlinear Volterra feed-forward section up to the second order can efficiently compensate effects of nonlinearity of the transmitting LED and performs up to 5 dB better in terms of optical power than using a standard DFE.