Net 4.5 Gb/s Single-Pixel-LED and 4-bit-DAC Based UOWC System Using NWF and MLSE

We experimentally demonstrate a net data rate of 4.5 Gb/s underwater optical wireless communication (UOWC) system using a single-pixel mini-LED and a 4-bit DAC over a 2-m underwater channel. The enabling DSP block includes a digital pre-distortion, a digital pre-emphasis, and a digital resolution enhancer in the transmitter DSP. Noise whitening filter (NWF) and maximum-likelihood sequence estimation (MLSE) are used at the receiver to mitigate the enhanced noise caused by a feedforward equalizer. A 36% BER performance gain is achieved by using NWF and MLSE decoder.