Improved PEG construction of large girth QC-LDPC codes
Madiagne Diouf, David Declercq, M.P.C. Fossorier, Samuel Ouya, Bane V. Vasic · 2016
In this paper, we present an improvement of the PEG algorithm for constructing quasi-cyclic low-density parity-check (QC-LDPC) codes with large girth. We introduce the concept of PEG-undetectable cycles on the computation tree in the PEG algorithm for QC-LDPC codes and give a predictive method to avoid these undetected cycles. The aim is to select only the candidates that ensure the maximization of local girth for a code of girth g ≥ 10 and thus avoid a posteriori verification after the creation of a new edge i.e. keep the predictive philosophy of the PEG algorithm. The proposed method is applicable to both regular and irregular codes and also protograph type-I codes. Simulation results are presented to demonstrate the efficiency of our method in terms of minimum circulant permutation matrix pminand error performance.