US Patent 7231586 Multi-rate viterbi decoder

A method and system for decoding a data symbol sequence that has been previously encoded using one or more unique code word polynomials in which at least one unique code word polynomial is used more than once. A set of 2d-1 unique branch metrics is computed, using the unique code word polynomials, where d is the number of unique code word polynomials. The computed set of 2d-1 unique branch metrics is stored in a memory. Path metrics are then calculated, based on the stored set of 2d-1 unique branch metrics. A decoded data symbol sequence is generated based on the computed path metrics.