Insertion/deletion correction by using parallel-interconnected viterbi decoders

Abstract

A new insertion/deletion correction scheme is presented for standard convolutional codes that makes use of multiple parallel-interconnected Viterbi decoders. Whenever an insertion or deletion error occurs, the connections between different Viterbi decoders ensure that decoding will proceed from the decoder that is in synchronization. In this way, a larger Viterbi decoder is created that can correct insertion and/or deletion errors by extending the Viterbi algorithm to encompass all parallel decoders. Further, it is shown how the performance can be improved by inverting certain bits during the encoding of the convolutional codes. This lowers the frequency of occurrence of repeating sequences, which is detrimental to synchronization when dealing with insertions/deletions.