Research On Super FEC Technology In High Speed Optical Communication System

With the rapid development of communication technology,optical communication systems also have higher requirements for transmission distance,channel capacity and transmission rate.In order to solve these problems better,it is necessary to study the super FEC schemes with better performance.Concatenated code is one of many code types that has good performance in correcting burst and random errors,and can maintain low redundancy,so it has become the main research object.Firstly,the optical communication system and channel FEC coding theory are analyzed and studied,and then two new RS-BCH codes are proposed based on the simulation analysis of a cascaded code proposed by predecessors.In theory,they are compared and analyzed,and the corresponding modeling and simulation are carried out.One is the cascaded code combining RS(255,239)code and BCH(31,16)code,and the other is the cascaded code combining RS(255,239)code and BCH(511,448)code,The error correction performance of these two concatenated codes has been greatly improved compared with the single RS(255,239)code and the original code,and the latter has moderate redundancy and is easy to implement.Based on the research of RS(1023,1007)+bch(2040,1952)code proposed in G.975.1 protocol,this paper also proposes a new bch-bch interleaved concatenated code,namely BCH(511,448)+bch(511,448)code.Compared with the previous code types,the outer code is changed to BCH code,which is shorter than RS code and has better performance,Compared with RS(1023,1007)+ BCH(2040,1952)interleaved concatenated code,RS(255,239)+ BCH(255,223)interleaved concatenated code,RS(255,239)+ BCH(31,16)interleaved concatenated code,RS(255,239)+ BCH(511,448)interleaved concatenated code,RS(255,239)code and various uncoded code schemes specified in G.975.1 protocol,the signal-to-noise ratio of this new bch-bch interleaved concatenated code is at least about 0.5d B better than other code types at the same bit error rate,That is,the performance is better than all code types except RS(255,239)+bch(31,16)code with high redundancy,and the coding redundancy is low,which is 30.1%,so it is more suitable for high-speed optical communication systems.