List Decoding

This chapter is devoted to list decoding of convolutional codes, which has been thoroughly analyzed here. The error-correcting capability of the code is fully exploited. A suitable code was first chosen and then the decoder was designed in order to ?>squeeze all juice?> out of the chosen code. In list decoding, the resources of the decoder were first limited; then a generator matrix was chosen with a state space that is larger than the decoder state space. Thus, assuming the same decoder complexity, a more powerful code can be used with list decoding than with Viterbi decoding. This chapter makes an important conclusion that there are situations when it is important that a convolutional encoder is systematic.