LDPC (Low Density Parity Check) coded modulation hybrid decoding. A novel
approach is presented wherein a combination of bit decoding and symbol
level decoding (e.g., hybrid decoding) is performed for LDPC coded
signals. Check node updating and symbol node updating are successively
and alternatively performed on bit edge messages for a predetermined
number of decoding iterations or until a sufficient degree of precision
is achieved. The symbol node updating of the bit edge messages involves
using symbol metrics corresponding to the symbol being decoded as well as
the bit edge messages most recently updated by check node updating. The
check node updating of the bit edge messages involves using the bit edge
messages most recently updated by symbol node updating. The symbol node
updating also involves computing possible soft symbol estimates for the
symbol during each decoding iteration.