Coding and signal processing in M-ary optical recording systems

We describe how ML technology writes nonbinary marks on the binary media and explain the coding and signal processing involved. The channel and noise modeling of the novel optical recording system is of importance. We investigate the new channel and noise models and apply the sufficient-statistics discrete-time channel. The performance of uncoded and coded systems with 8 levels are compared against the channel capacity. Soft iterative decoding is useful to an improvement of a standard DVD system. We obtain soft decoder of EFM code and DVD code. The soft iterative decoding the concatenated code shows iterative gain over hard decoding approach. Soft equalizer with less complexity than BCJR detector is essential to implementable soft iterative decoding of high-density optical recording system. We investigate a bidirectional-arbitrated decision-feedback equalizer(BAD) and extend its use to produce soft-output BAD(S-BAD). It is shown to have less complexity than the BCJR detector while providing satisfactory performance with small gap and error events.