Design of Rate-Compatible Irregular LDPC Codes Based on Edge Growth and Parity Splitting

This paper considers the design of rate-compatible low-density parity-check (LDPC) codes with optimized degree distributions for their corresponding rates. The proposed design technique is based on extension, where a high-rate base code, or daughter code, is progressively extended to lower and lower rates such that each extension code is compatible with the previously obtained codes. Specifically, two well-known parity matrix construction methodologies, edge growth and parity splitting, are adapted to yield a flexible framework for constructing rate- compatible parity check matrices with a uniform performance characteristic. The design examples provided are based on extrinsic information transfer (EXIT) chart optimizations and demonstrate good performance up to rates as low as 1/5.