一种快速编码的半随机LDPC码构造研究

摘要

Low density parity check(LDPC)code has excellent error correction performance which approaches to Shannon limits,and widely applied in the field of channel encoding. However,the encoding complexity of the LDPC code is the promi⁃nent problem which restricts its universal applications. The encoding complexity and decoding performance of LDPC code are de⁃termined by the parity check matrix structure directly. The construction method of semi⁃random LDPC code parity check matrix based on quasi dual⁃diagonal structure is proposed. It has excellent error correction performance and low encoding complexity of LDPC code fitting with IEEE 802.16e standard,more flexibility design in code rate,code length,basis check matrix,extended factor and so on,and better satisfies the demands of engineering practice. Taking(16384,8192)LDPC code as an example to proceed fast iterative encoding,the excellent decoding performance is obtained with the proposed construction method. It can be used to realize LDPC decoders design of high speed and low complexity.%低密度奇偶校验码（LDPC码）具有逼近Shannon限的优异纠错性能，在信道编码领域的应用越来越广泛，但是LDPC码的编码复杂性一直是制约其普遍应用的突出问题。奇偶校验矩阵的结构则直接决定着LDPC码的编码复杂度和译码性能。提出一种准双对角线结构的半随机LDPC码奇偶校验矩阵的构造方法，它具有IEEE 802.16e标准LDPC码的优异纠错性能和低编码复杂度，同时在码率、码长、基础校验矩阵和扩展因子等设计方面更具灵活性，能更好地适应工程实践的需要。采用这种构造方法，以（16384，8192）LDPC码为例进行快速迭代编码，能够获得优异的译码性能，可以用于实现高速率低复杂度的LDPC译码器设计。