Patent ID: 8190980

Claim:
An apparatus comprising: a parser that is configured to identify at least one predetermined field in a received encoded message sequence that comprises a plurality of fields, the at least one predetermined field comprising values that are known; means for generating data representing at least one state with reduced uncertainty for the at least one predetermined field in the encoded message sequence, wherein a state with reduced uncertainty is a state of a trellis-based decoding process that is associated with the at least one predetermined field of the encoded message sequence such that when decoding the encoded message sequence with the trellis-based decoding process a maximum likelihood path of the trellis-based decoding process passes through one or more states of reduced uncertainty by the end of the at least one predetermined field and thereby reduces a number of candidate paths for the encoded message sequence for states that are not states with reduced uncertainty, and wherein the parser is further configured to set a metric associated with a state of the encoded message sequence such that a state with reduced uncertainty is set to a higher probability value than for a state that is not a state with reduced uncertainty; and a decoder configured to connect to the means for generating data representing at least one state with reduced uncertainty, wherein the decoder is configured to decode the encoded message sequence with the trellis-based decoding process.