A Bound on Viterbi Decoder Error Burst Length

Abstract

A maximum likelihood (Viterbi) decoder used with a convolutional code on a Gaussian channel produces decoding errors which tend to occur in clusters or bursts. A method is described for deriving an upper bound on the probability of occurrence of error bursts of a given length. The method applies to the optimum convolutional codes found by Odenwalder, for which the codeword weight distribution is partially known. Laboratory measurements of error burst length at signal-to-noise ratios greater than 4 dB indicate that the upper bound is useful for approximating the length of high-probability bursts, but is not precise enough to predict the probability of very long, low-probability bursts.