一类改进的Gallager方法构造的低密度校验码

A Class of Improved Low-Density Parity-Check Codes Constructed Based on Gallager′s Form

针对短环对有限长LDPC迭代译码性能的劣化,提出了一类基于Gallager方法构造的低密度校验码。该方法在保留Gallager构造基本形式的基础上,采用了类似准循环的构造形式,使生成的码字不受短环的干扰并具有好的距离特性。仿真结果表明,改进的编码在分组长度较短时甚至优于Gallager码的性能。

Focused on the problem that short cycles degrade the iterative decoding performance of finite length LDPC, a class of improved low - density parity - check codes constructed based on Gallager＇s form is designed. On the basis of keeping down the basic form of Gallager＇s construction,a quasi- cyclic form is used, then the new codes are free of cycles of length and have good minimum distance. Simulation results demonstrated that the modified codes is better than Gallager codes when block length is small.