Code Annealing and the Suppressing Effect of the Cyclically Lifted LDPC Code Ensemble
Code annealing, a new method of designing good codes of short block length, is proposed, which is then concatenated with cyclic lifting to create finite codes of iow frame error rate (FER) error floors without performance outliers. The stopping set analysis is performed on the cyclically lifted code ensemble assuming uniformly random lifting sequences, and the suppressing effect/weight of the cyclic lifting is identified for the first time, based on which the ensemble FER error floor can be analytically determined and a scaling law is derived. Both the first-order and high-order suppressing effects are discussed and quantified by different methods including the explicit expression,an algorithmic upper bound, and an algebraic lower bound.The mismatch between the suppressing weight and the stopping distances explains the dramatic performance discrepancy among different cyclically lifted codes when the underlying base codes have degree 2 variable nodes or not. For the former case,a degree augmentation method is further introduced to mitigate this metric mismatch, and a systematic method of constructing irregular codes of low FER error floors is presented. Both regular and irregular codes of very low FER error floors are reported,for which the improvement factor ranges from 106-104 when compared to the classic graph-based code ensembles.
Chih-Chun Wang
School of Electrical & Computer Engineering Purdue University West Lafayette, IN 47907, USA
国际会议
2006年IEEE信息理论国际会议(Proceedings of 2006 IEEE Information Theory Workshop ITW06)
成都
英文
86-90
2006-10-22（万方平台首次上网日期，不代表论文的发表时间）