Viterbi decoding considering insertion/deletion errors

High recording density is required in digital recording systems. However, as the recording density increases, the error rate also increases. It is known that burst errors called synchronization errors, caused by insertion/deletion errors, occur in optical recording systems more frequently than in other disk systems. We propose a Viterbi decoding method based on the Levenshtein distance. We show that the Levenshtein distance is a suitable metric for a channel where both substitution errors and insertion/deletion errors occur. Our proposal makes it possible to continue Viterbi decoding without re-synchronization even if some insertion/deletion errors occur in a channel.