Partial Response Maximum Likelihood Decoding

Abstract

A partial response maximum likelihood decoder, such as a Viterbi decoder, implements a set of combined states where each combined state can represent at least two states from a plurality of complementary sets of states. For each data symbol and each combined state, a Viterbi processor (703) determines a path metric and a substate indication for each path to the combined state. A path selection processor (709) of the Viterbi processor (703) selects a selected path and a selected sub state indication for the path which corresponds to a highest likelihood path metric. The substate indication is an indication of which of the complementary set of states the combined state represents for the data symbol. The invention allows a substantial complexity reduction and/or reduced computational burden as the Viterbi algorithm can be applied to a reduced number of combined states.

Dependencies are inferred from the claim text.