Abstract:

In order to verify the influence of different water quality conditions on underwater optical communication,the Monte Carlo simulation algorithm is used to simulate the discrete impulse response of the underwater optical channel.Combined with the Orthogonal Frequency Division (OFDM) and strong anti-fading ability,the underwater optical communication system is built based on the OFDM.With known channel state information at the receiver and the transmitter,the 16 Quadrature Amplitude Modulation is used,and the Monte Carlo construction algorithm is applied to construct the polar codes.The CRC-Aided Successive Cancellation List polarization decoding algorithm is used to design the polar codes in OFDM-based underwater optical communication.The influence of parameters such as code length on the performance of polar codes under different water quality conditions is verified by experiments.It is also proved that compared with the low-density parity check(LDPC) codes of the same code length,the polar codes get a performance gain of 0.2dB~0.6dB at the high signal noise ratio.As the water quality environment worsens,its progressive performance becomes more obvious,and there will be no error leveling problem.In addition,the polar codes have a simpler coding structure,the decoding complexity is not much different from that of LDPC codes,and multiple iterations are not required in decoding.Since polar codes have a lower coding and decoding complexity than other coding schemes,polar codes have strong competitiveness and application potential in underwater optical communication scenarios.

Key words: optical communication, polar codes, monte carlo simulation algorithm, orthogonal frequency division multiplexing, 16 quadrature amplitude modulation