Iterative sequential decoding

It is shown that use of a two-stage decoding procedure consisting simply of an inner stage of block decoding and an outer stage employing a single sequential decoder does not result in an improvement in the computational overflow problem for the sequential decoder. Improvement can, however, result from use of multiple sequential decoders or use of a single sequential decoder with appropriate scrambling. Although the performance improvement resulting from application of these techniques to the additive white Gaussian noise channel is not significant, implementation and rate advantages make iterative sequential decoding techniques worth pursuing. Ia particular, with these techniques, a sequential decoder for a binary symmetric channel can be used regardless of the physical channel characteristics. Such a "universal" decoder is expected to be both simple and capable of high rate operation.