New construction of rate-compatible block-type low-density parity-check codes using splitting

Abstract

In this paper, we construct rate-compatible block-type low-density parity-check (B-LDPC) codes using splitting that cover a wide range of code rates from 1/3 to 4/5. They outperform other rate-compatible B-LDPC codes for all rates and can be decoded conveniently and efficiently. A strong motivation for proposing splitting scheme comes from the observation that the quality of the initial transmission is the most important factor to achieve high throughput of type-II HARQ. Proposed scheme builds low-rate codes from high-rate codes by splitting rows of the given LDPC parity-check matrix. Thus, rate-compatible LDPC codes obtained by splitting have good FER (Frame Error Rate) performance in the first transmission. Contrary to other rate-control methods such as puncturing, shortening, and extending, the splitting algorithm not only needs smaller number of operations but also shows faster decoding convergence speed since more efficient Tanner graph is used for the decoding.