Concatenated single-parity check codes for high-density digital recording systems

2006 by Taylor & Francis Group, LLC. The breakthrough of turbo codes [1] and low-density parity check codes [11, 37] has revolutionized the coding research with several new concepts, among which code concatenation and iterative decoding are being actively exploited both for wireless communications and future digital magnetic recording systems. After being precoded, filtered and equalized to some simple partial response (PR) target, the magnetic recording channel appears much like an intersymbol interference (ISI) channel to an outer code and, hence, many of the techniques used in concatenated coding can be adopted. In particular, the observation that an ISI channel can be effectively viewed as a rate-1 convolutional code leads to the natural format of a serial concatenated system where the ISI channel is considered as the inner code and the error correction code (ECC) as the outer code.With reasonable complexity, iterative decoding and equalization (IDE), or turbo equalization, can be used to obtain good performance gains.

Concatenated single-parity check codes for high-density digital recording systems Chapter