Research On Channel Coding Technology And Application Based On Probabilistic Shaping Theory In Optical Communication

With the rapid development of the Internet,applications such as the Internet of Things,big data,cloud computing,and virtual reality are emerging one after another.New applications have put forward higher requirements for optical communication,and the transmission system can be optimized by using appropriate channel coding technology.Turbo code is a universal channel coding technology used by 3G/4G mobile communication technology.However,due to its iterative decoding,it has a high delay and cannot meet the ultra-high rate and ultra-low latency 5G requirements.Therefore,LDPC codes and The Polar code,the LDPC code is a data channel coding scheme,and the Polar code is a broadcast and control channel coding scheme.When an LDPC code is used,its finite length will result in an encoding gap,and the uniform input distribution of the LDPC code will cause an shaping gap.When probabilistic shaping technology is combined with LDPC,system mutual information can be improved,and transmission power and bit error rate can be reduced.Focusing on the above problems in channel coding in optical communication,this thesis combines probabilistic shaping technology with LDPC to carry out theoretical and experimental research on channel coding technology.The main innovations of the paper are as follows:1?The implementation method of probabilistic shaping coding in optical communication is designed.The AWGN channel simulation platform combining probability shaping with PAM4 modulation and PAM8 modulation is built.The PAM4 signal based on probability shaping is relatively evenly distributed.The PAM4 signal mutual information is increased by 0.1775bit./symbol,PAM8 signal based on probability shaping is relatively evenly distributed.PAM8 signal mutual information is increased by up to 0.2054 bit/symbol;2?The scheme of visible light communication system based on probabilistic shaping and PAM4 modulation was proposed and implemented for the first time,and the experimental test was completed..The experimental results show that compared with the evenly distributed PAM4 signal,the PAM4 signal based on probabilistic shaping can save up to 20.62%of the transmission power,the system transmission rate is increased by 22.64%,and the shaping gain is up to 1.396dB.3?The PAM4 and PAM8 fiber-optic communication system scheme based on probabilistic shaping is proposed and implemented.The simulation results show that the maximum improvement interval of PS-PAM4 mutual information based on probabilistic shaping is 0.1693bit/symbol,and the maximum shaping gain is 1.385dB.The maximum improvement interval of PS-PAM8 mutual information is 0.1632 bit/symbol,and the maximum shaping gain is 1.132 dB.When the probability shaping parameters are the same,the maximum mutual information of PS-PAM8 is larger,and the maximum shaping gain is also larger.4?The PM-16QAM optical fiber communication system based on probabilistic shaping is proposed and implemented.The simulation results show that the PM-16QAM based on probability shaping has lower bit error rate and the bit error rate is 10-3.At the same time,PS-PM-16QAM reduces the transmit power by 25%relative to the evenly distributed PM-16QAM.