MAX-LOG-MAP EQUIVALENCE LOG LIKELIHOOD RATIO GENERATION SOFT VITERBI ARCHITECTURE SYSTEM AND METHOD

摘要

A modified soft output Viterbi algorithm (SOVA) detector receives a sequence of soft information values and determines a best path and an alternate path for each soft information value and further determines, when the best and alternate paths lead to the same value for a given soft information value, whether there is a third path departing from the alternate path that leads to an opposite decision with respect to the best path for a given soft information value. The SOVA detector then considers this third path when updating the reliability of the best path. The modified SOVA detector achieves max-log-map equivalence effectively through the Fossorier approach and includes modified reliability metric units for the first N stages of the SOVA detector, where N is the memory depth of a given path, and includes conventional reliability metric units for the remaining stages of the detector.

主权项

1. A Viterbi detector comprising:
a soft output Viterbi algorithm (SOVA) detector adapted to receive a sequence of soft information values, the SOVA detector configured to determine a best path and an alternate path for each of these soft information values and further determine, when the best and alternate paths lead to the same value for a given soft information value, whether there is a third path departing from the alternate path that leads to an opposite decision with respect to the best path for a given soft information value, the SOVA detector further configured to utilize this third path when updating the reliability of the best path, where the SOVA detector includes first reliability metric units for the first N stages of the SOVA, detector, where N is the memory depth of a given path, and includes second reliability metric units different that the first reliability metric units for the remaining stages of the SOVA detector.