非二进制准循环低密度校验码的性能研究

Performance analysis of NB-QC-LDPC code

为提高100Gbit/s光通信系统的传输距离,构造了高增益的NB-QC-LDPC(非二进制准循环低密度校验码),这种纠错码构建在伽罗华域上,适合于采用QPSK(正交相移键控)或DQPSK(差分正交相移键控)调制格式的100Gbit/s系统。文章采用对数傅里叶和积译码算法分析了NB-QC-LDPC的误码性能。结果表明,与二进制准循环低密度校验码相比,码长为500、码率为0.8的NB-QC-LDPC,在误码率为10-8时可提供约1dB的编码增益。同样,在误码率为10-8时,若码率从0.9降低至0.8,NB-QC-LDPC能多提供约0.6dB的编码增益,即在低码率时,NB-QC-LDPC具有更好的性能。

In order to increase the transmission distance of 100 Gbits/s optical communication systems, this paper constructs a high-gain Non-Binary Quasi-Cyclic Low-Density Parity Check （NB-QC-LDPC） code over the Galois Field GF（4）, which is suit- able for 100 Gbit/s optical communication systems using QPSK or DQPSK modulation formats. Using the Logarithm Fourier Sum-Product Algorithm （Log-Fourier SPA）, it analyzes the BER performance of NB-QC-LDPC. The results show that compared with the binary QC-LDPC code, the NB-QC-LDPC code with a code length 500 and code rate 0.8 can provide approxi mately 1 dB coding gain at the BER of 10 8 and when the code rate decreases from 0.9 to 0.8 at the same BER, this code can provide additional code gain of about 0.6 dB, which means that the NB-QC-LDPC code outperforms the binary QC-LDPC code at the lower code rates.