Improved Information Nulling Algorithm and Extending Check Matrix Algorithm for Rate Compatible LDPC Codes

摘要

This paper focuses on two rate compatible algorithms that make the code rate of Low-Density Parity Check (LDPC) code lower, the Extending Check Matrix algorithm (ECMA) and the Information Nulling algorithm (1NA). ECMA adds new parity check bits, while INA replaces several information bits with dummy bits that are known to decoder. Theoretical analysis and simulation results indicate that for irregular LDPC code. INA can be improved remarkably by padding the coded bits with lower degree first. Further comparison implies that improved INA and ECMA may complement each other. For a specific target coding rate, ECMA is suitable for coarse rate compatible (RC) in a wide range of coding rate, and improved INA is fit for fine rate adjustment. Thus the code rate of RC-LDPC codes can be lowered bit by bit, just as the puncturing algorithms rise the coding rate.