  An algorithm of improving the performance of iterative decoding on
perpendicular magnetic recording is presented. This algorithm follows on the
authors' previous works on the parallel and serial concatenated turbo codes and
low-density parity-check codes. The application of this algorithm with
signal-to-noise ratio mismatch technique shows promising results in the
presence of media noise. We also show that, compare to the standard iterative
decoding algorithm, an improvement of within one order of magnitude can be
achieved.
