Arbitrary Bit Generation and Correction Technique for Encoding QC-LDPC Codes with Dual-Diagonal Parity Structure

In this paper, we propose a simple yet low complex systematic LDPC encoding method for class of quasi-cyclic low-density parity-check (QC-LDPC) codes which have an efficient encoding/decoding algorithm due to the simple structure of their parity-check matrices. The proposed encoding method is applicable to parity-check matrices having dual-diagonal parity structure with single column of weight 3. Unlike finding a direct solution for parity bits in schemes (Richardson and Urbanke, 2001 and Classon and Blankeship, 2004), the proposed scheme first generates arbitrary parity bits. Then, given the parity bits for the first sub-block and exploiting the dual-diagonal structure, all parity bits are found through correction. With slight modification of parity-check matrix H, proposed LDPC encoding scheme is directly applicable to matrices defined in IEEE physical layer standards with almost negligible performance loss. Moreover, the overall computational complexity involving encoding process is lower than well-known Richardson´s efficient encoding scheme (Richardson and Urbanke, 2001).