任意列重大围长QC-LDPC码的确定性构造  

Deterministic Construction of QC-LDPC Codes for Any Column Weight with a Large Girth

作　　者：张轶[1] 达新宇[1] 苏一栋[1] 

机构地区：[1]空军工程大学信息与导航学院,陕西西安710077

出　　处：《电子学报》2016年第8期1814-1819,共6页Acta Electronica Sinica

基　　金：国家自然科学基金(No.61271250)

摘　　要：针对准循环低密度奇偶校验(Quasi-Cyclic Low-Density Parity-Check,QC-LDPC)码中准循环基矩阵的移位系数确定问题,提出基于等差数列的确定方法.该方法构造的校验矩阵围长为8,列重可任意选取,移位系数由简单的数学表达式确定,编码复杂度与码长呈线性关系,节省了编解码存储空间.研究结果表明,列重和围长是影响码字性能的重要因素.在加性高斯白噪声(Additive White Gauss Noise,AWGN)信道和置信传播(Belief Propagation,BP)译码算法下,该方法构造的码字在短码时可以获得与IEEE 802.11n、802.16e码相一致的性能,在长码时误比特率性能接近DVB-S2码.同时表明该方法对码长和码率参数的设计具有较好的灵活性.To cope with the issue of determining cyclic shift coefficients of the quasi-cyclic sub-matrix in the Quasi-Cyclic Low-Density Parity-Check （QC-LDPC）codes,a method was presented based on the arithmetic progression to com-pute the cyclic shift coefficients.By this method,a class of girth eight QC-LDPC codes for any column weight is obtained, and the cyclic shift coefficients can be expressed in simple analytic expressions to reduce required memory usage.Mean-while,the encoding complexity is linearly proportional to code length due to the lower triangular parity matrix.The simula-tion result shows that column weight and girth have important influences on code performance.Furthermore,over an Addi-tive White Gauss Noise （AWGN）channel and under the Belief Propagation （BP）decoding algorithm,the simulation re-sults represent that bit error rate of the proposed QC-LDPC codes is no less than the LDPC codes in IEEE 802.11n and 802. 16e with short code length,and is close to the LDPC codes in DVB-S2 with long code length.Moreover,the study result also confirms that the proposed algorithm has high flexibility with respect to the design of code length and rate.

关 键 词：准循环低密度奇偶校验码 列重 围长 准循环基矩阵 高效编码 

分 类 号：TN911.22[电子电信—通信与信息系统]