On the Construction of Low Error Floor LDPC Codes on Rectangular Lattices

In previous literature, arithmetically constrained slope sequences have been adopted for the construction of girth eight (3, k) LDPC codes on rectangular lattices. This method, however, creates a certain number of small trapping sets, which degrade overall performances. In this letter, an improved construction of a class of (3, k) LDPC codes on rectangular lattices is presented. Relevant constraints are derived to eliminate small trapping sets to improve performance in the error floor region. The check matrices of the proposed codes are introduced into quasi-cyclic structures, where experimental investigation shows favorable error rate performance over AWGN channels.