【摘要】 校验矩阵右半部分双对角线上的子矩阵均为单位阵,该确定性单位阵的存在不仅破坏了准循环低密度奇偶校验(QC-LDPC)码的随机性,使得码字性能有一定的损失。为此,提出一种围长为8、可快速编码的QC-LDPC码构造方法。该方法采用独立行列映射序列(IRCMS)算法、行列循环移位和掩码技术得到一种改进型准双对角结构的校验矩阵,使得所构造的码字不仅围长至少为8,而且可利用校验矩阵直接进行快速编码,可有效降低编码复杂度。仿真结果表明,与基于IRCMS算法构造的规则码相比,所构造的码字不仅具有快速编码特性,而且性能提升0.15 dB左右。与基于渐近边增长算法构造的QC-LDPC码相比,所构造的码字在低编码复杂度的基础上性能与之相近。与可快速编码的改进型DVB-S2码相比,所构造码字有0.1 dB左右的编码增益。更多还原

【Abstract】 The sub-matrices on both diagonals of the right half of the check matrix are unit matrices. Existence of the deterministic unit matrix not only destroys the randomness of Quasie Cyclic-Low Density Parity Check(QC-LDPC)code,it leads to a certain loss of performance. For this reason,a construction method of QC-LDPC codes with girth 8 and a fast encoding is proposed. An improved quasi-doubly-diagonal parity check matrix is obtained by using Independent Row-column Mapping Sequence(IRCMS) algorithm, row and column rotation shift and masking techniques, so that the constructed codes not only have a girth of at least 8,but also use check matrix to fast coding,they can effectively reduce the coding complexity. Simulation results show that compared with the rule-based codes constructed based on IRCMS algorithm,the constructed codes not only have fast coding characteristics,but also have a performance improvement of about 0. 15 dB. Compared with the QC-LDPC codes constructed based on the Progress Edge Growth(PEG) algorithm,the constructed codes are similar in performance with low coding complexity. Compared with the improved DVB-S2 codes,the constructed codes have a coding gain of about 0. 1 dB.更多还原