Convolutional codes for channels with substitutions, insertions, and deletions
We introduce modifications to common convolutional decoders to accommodate channels with Insertions and deletions. For the Viterbi decoder, new states are added to the trellis diagram to represent the new situation and the expansion algorithm is modified accordingly. For sequential decoding, we provide modifications to the stack algorithm and a new metric is introduced. Also, we developed a systematic way for convolutional code construction using Simulated Annealing so as to maximize the distance between codewords In the presence of insertions and deletions. The proposed techniques are shown to be superior to previous approaches for this problem, and have no additional code overhead.