Transmission of RF frequency by MIMO-LED system for underwater turbulent channel link

Abstract In this paper, an experimental system for underwater wireless optical communications (UWOC) is designed on a lab scale. An amplitude shift key (ASK) modulation is used for modulating the frequency of the white LED light with a multiple input-multiple output (MIMO) technique. A solar cell and a photodiode (BPX61) are used as a detector to receive these frequencies and then compare the performances. Water turbidity was increased to investigate the effect on received frequencies by adding different concentrations of the hydroxyls Al(OH)3 and Mg(OH)2. We examined the (Vpp, SNR, and Av) parameter values to assess the quality of the proposed link. The lowest values of SNR are achieved by adding the fifth concentration C5 of suspended particles to the water with a solar cell in the receiver. Furthermore, the highest values of SNR are obtained by adding the first concentration C1 with the use of the photodiode detector (BPX61). The results show that the solar cell cannot be sensitive to the signal after 75 kHz. While the photodiode (PBX61) can be sensitive to the signal up to 300 kHz at the five concentrations of suspended particles.