Abstract: For any row weight L, a new family of （3, L）-regular Low-Density Parity-Check（LDPC） codes is proposed explicitly with girth eight as the first component code. Another Low-Density Parity-Check（LDPC） codes with the capacity of fast encoding is proposed as the second component code. Employing these new codes  in the construction method of Chinese Remainder Theorem（CRT）, a novel class of compound QC-LDPC codes is presented with both girth at least eight and very flexible code lengths. The proposed codes have the above two characteristics. Simulation results show that compared with QC-LDPC code constructed by IRCMS algorithm, the proposed codes have comparable or even better performance, while the encoding complexity is lower; moreover, the proposed codes outperform the array code with dual-diagonal parity structure about 0.3 dB gain at BER of 10－4 with the capacity of fast encoding. Compared with PEG-CRT-LDPC codes, the proposed codes have better performance while the encoding complexity is lower.

Key words: Low-Density Parity-Check（LDPC） code, Chinese remainder theorem, component code, fast encoding

摘要： 对于任意行重L，利用完全确定的方式构造出一类围长为8的（3，L）-LDPC码作为分量码1，构造可快速编码的LDPC码作为分量码2，利用分量码1和分量码2，并结合中国剩余定理（CRT）构造出一类围长至少为8的合成QC-LDPC码。该方法构造出来的码字同时具备以上两种特性。仿真结果表明，所构造的码字性能与基于IRCMS算法构造的QC-LDPC码相比，有略微提升，且具有快速编码特性，编码复杂度更低；与具有双对角结构的阵列码相比，性能有了明显提升。在误码率达到10－4时，码字性能大约提高了0.3 dB；与PEG-CRT-LDPC码相比，所构造的码字在低编码复杂度的基础上性能有所提升。

关键词: 低密度奇偶校验（LDPC）码, 中国剩余定理, 分量码, 快速编码