Marker Codes on BPMR Write Channel With Data-Dependent Written-in Errors

The performance of bit-patterned media recording is limited, in part, by written-in errors in the write channel, which has recently been modeled by a channel introducing data-dependent insertion, deletion, and substitution (DIDS) errors. The Davey-MacKay (DM) construction has shown promising error performance on the DIDS channel, where synchronization errors are sparse and burst error lengths before and after each synchronization error are short. In this paper, we consider marker codes with a nonbinary low-density parity-check code as the outer code for the DIDS channel. Our contributions are twofold. First, we propose two computationally efficient inner decoding schemes for the DM and marker code constructions. One is suitable when the burst errors in the DIDS channel are short, and the other when the burst errors are long. Second, our computer simulations show that marker codes can increasingly outperform DM codes as the burst error length increases, and thus provide greater robustness against burst errors on the DIDS channel.