High speed underwater visible light communication system based on LED employing maximum ratio combination with multi-PIN reception

In this paper, we proposed an underwater visible light communication system utilizing QAM-DMT and Multi-PIN reception to do the MRC receiving. The transmitter is a 600 mu m x 600 mu m green-emitting silicon substrate LED which has a peak emission wavelength of 521 nm. We study the effect of quiescent working point of the LED, the zero-padding number, the ISFA tap number and the ratio of two receivers on the BER performance of our VLC system. We notice that the ratio of two receivers can remarkably affect the performance of our system. We also measured the BER performance versus the bandwidth of the signal in 32QAM, 64QAM and 128QAM modulation format and we find the highest data rate of our system can reach 2.175 Gb/s. As far as we know, it is the highest data rate in under pure water VLC system using commercial LED and a PIN receiver.