Improving Burst Error Tolerance of LDPC-Centric Coding Systems in Read Channel

We report on the use of low-density parity check (LDPC)-centric error correction coding (ECC) for magnetic recording read channel in the presence of significant burst errors. Since an LDPC code by itself is severely vulnerable to burst errors due to its soft-decision probability-based decoding, we focus on LDPC-centric concatenated coding in which LDPC code is used as inner code. To improve the burst error tolerance, we propose a hybrid LDPC-centric concatenated coding strategy in which one inner LDPC codeword is replaced by another codeword with much stronger burst error correction capability. This special inner codeword reveals the burst error location information, which can be leveraged by the inner LDPC code decoding to largely improve the overall robustness to burst errors. Using a hybrid BCH-LDPC/RS concatenated coding system as a test vehicle, we demonstrate a significant performance advantage over its RS-only and LDPC-only counterparts in the presence of three different types of burst errors.