Design of Rate-Compatible Low-Density Parity-Check Codes with Constant Check Matrix

In this paper, we propose a “bit duplication” design method for rate-compatible low-density parity-check codes (LDPC). The main idea of the method is to change the structure of codewords during its transmission over the communication system. This method can be effectively applied to create a set of codes, allowing to obtain lower-rate codes from the mother codes. To evaluate the proposed method, the dependence of the bit error probability on the signal-to-noise ratio (SNR) was simulated in Matlab. The result shows that the proposed method is superior to the conventional method of puncturing information bits.