Symbol by symbol map detection for signals corrupted by colored and/or signal dependent noise

摘要

Symbol by symbol MAP detection for signals corrupted by colored and/or signal dependent noise. A novel means is presented for recursive calculation of forward metrics (α), backward metrics (β), and corresponding soft information (e.g., which can be provided as LLRs (log likelihood ratios)) within communication systems in which a trellis can be employed to perform demodulation of a received signal sequence. For signals that have been corrupted by colored and/or signal dependent noise, this means provides for the ability to perform novel soft information calculation for subsequent use in iterative decoding processing. Many types of communication channels can benefit from this novel means of detection including communication channels within hard disk drives (HDDs).