基于双序列反序的(4,L)规则girth-8 QC-LDPC短码OA

The explicit construction of short-length quasi-cyclic(QC)low-density parity-check(LDPC)codes with larger girth is of critical importance for both theoretical research and practical applications in QC-LDPC codes.Initially,a greedy search algorithm based on a pairing strategy is introduced,and empirical results at column weight J equal to 4 guides the formulation of an exponent matrix characterized by dual-sequence reordering.Subsequent analysis demonstrates that this exponent matrix corresponds to QC-LDPC codes with a girth of 8 for any row weight L.Compared to existing explicit construction methods,specifically the greatest-common-divisor method,the proposed QC-LDPC codes significantly reduce the code length.Finally,techniques involving the segmentation and concatenation of the exponent matrix,combined with masking procedures,are employed to design composite codes.These codes exhibit decoding performance surpassing 5G NR LDPC codes in high signal-to-noise ratio regions.