Patent ID: 7765458

Claim:
A method for determining potential error patterns, the method comprising: detecting information that was previously encoded based on a trellis to provide detected information; decoding the detected information based on the trellis to provide decoded information, wherein the decoded information corresponds to a winning path through the trellis that ends at a winning state; identifying at least one alternate path through the trellis that ends at the winning state, wherein the at least one alternate path includes a trace back portion and a non-trace back portion; determining a trace back depth associated with the trace back portion of the at least one alternate path; and generating a potential error pattern based on the winning path and one of the at least one alternate path, wherein said identifying the trace back portion of the at least one alternate path comprises starting from the winning state, tracing back paths through the trellis for a number of trellis stages, wherein the number of trellis stages is based on the trace back depth.