Research on the Performance of the LDPC-OQPSK System Used in Underwater Wireless Optical Communication

Under the novel ocean turbulence model of exponential-generalized gamma (EGG) distribution, low density parity check (LDPC) coding is introduced into underwater communication system modulated by the offset quadrature phase shift keying (OQPSK). The signal-to-noise ratio (SNR) gains of LDPC-OQPSK coded joint modulation system are simulated at different turbulence intensities and water qualities. It obtains SNR gain of 5.355
$dB$
in the clear seawater when the scintillation index is 0.2. Finally, a blue light communication setup is built to research the bit error rate (BER) performances of underwater LDPC-OQPSK.