Performance of efficiently encodable low-density parity-check codes in noise bursts on the EPR4 channel

We consider in this paper the possibility of using a low-density parity-check (LDPC) code as the complete error control system in a magnetic recording channel. We compare the performance of selected LDPC codes with two Reed-Solomon (RS) code schemes on an extended partial-response class 4 (EPR4) channel, with particular emphasis on their performance in noise bursts (induced by media defects or thermal asperities). We quantify the performance of LDPC codes in noise bursts via a maximum-burst-length parameter, and we present a simple algorithm for computing this parameter. We find some very promising initial results: the LDPC codes are very robust against large noise bursts (128 bits long or more), and are superior to the RS schemes examined in the measurable error rate region. The extent to which they are superior depends on the particular LDPC scheme involved, and the results provide motivation for further investigation in this area.