Iterative decoding for concatenated error correction coding in PRML channel systems

A new iterative decoding scheme was developed for the cyclic redundancy check error correction code (CRCC), a concatenated error correction coding system. This simple iterative decoder achieves efficient cooperation between an outer Reed-Solomon error correction code (RS-ECC) decodes and a PRML trellis-detector. By using “error-free” decoded bit-information feedback from the outer RS-ECC decoder, the iterative scheme employs “state pinning” in the ML trellis-detector. This enables long error-events in the ML-decoded data to be corrected efficiently without adding extra coding redundancy and specific decoding complexity. The iterative scheme improves the correction capability of the outer RS-ECC coding by making use of a CRCC coding for specific correcting short error-events. Simulation shows that the iterative scheme achieves significant improvement in RS-ECC error-rate performance for a rate 16/17 quasi-MTR-coded Modified E²PRML (ME²PRML) channel in conjunction with CRCC coding