Patent Document ID: 7721187
Application ID: 11860668
Patent Flag: 1

Claim One:
1. A decoder that is operative to perform radix-4 SOVA (Soft Output Viterbi Algorithm) decoding of a signal, the decoder comprising: an ACS (Add Compare Select) module that is operative to: receive a plurality of state metrics and a plurality of branch metrics corresponding to each state of plurality of states of a trellis at a previous trellis stage located two trellis stages from a current trellis stage; process the plurality of state metrics and the plurality of branch metrics to generate a first hard decision for a bit within the signal corresponding to the current trellis stage and a second hard decision for a bit within the signal corresponding to a previous trellis stage located one trellis stage from the current trellis stage; and process the plurality of state metrics and the plurality of branch metrics to generate a first reliability of the first hard decision and a second reliability of the second hard decision; and wherein: an REX (Register Exchange) module that is operative to process the first hard decision, the first reliability, the second hard decision, and the second reliability to make an estimate of at least one information bit encoded within the signal.