Patent ID: 8489972

Claim:
A decoding method of decoding N received branchwords produced by a convolutional encoder using a tail-biting convolutional code, comprising: storing the N received branchwords in memory; successively performing Viterbi updates on a sequence of branchwords, the sequence comprising a first block comprising S consecutive branchwords from the N received branchwords, a second block comprising the N received branchwords, and a third block comprising T consecutive branchwords from the N received branchwords, where S and T are less than N, and where the Viterbi updates generate updated path metrics; determining a first encoder state at the end of the third block most likely to have generated the final branchword in the sequence from the best path metric; first performing a Viterbi traceback procedure from that first encoder state at the end of the third block to determine a second encoder state at the start of the third block of branchwords; second performing a Viterbi traceback procedure from that second encoder state at the start of the third block to determine a third encoder state at the start of the second block of branchwords; and outputting a derived tail-biting path, if the second and third encoder states are identical.