Viterbi decoder and decoding method using rescaled branch metrics in add-compare-select operations

摘要

A Viterbi decoder and method rescale branch metrics by a minimum value of a prior state's path metric. A branch metric unit generates branch metrics from groups of bits of a received bit stream, and an ACS operation unit rescales the branch metrics and performs ACS operations to generate path metrics for the next state of the decoder. The rescaled branch metrics may be stored in branch metric registers of the ACS operation unit for use in a subsequent ACS operation. Rather than resealing path metrics within individual ACS elements, branch metric rescaling is performed outside the individual ACS elements.