On hybrid stack decoding algorithms for block codes

This correspondence presents sequential algorithms for soft decision decoding of linear block codes. They use a stack algorithm based on the trellis of the code. We are interested in the trellis as a means to avoid path-decoding repetitions. As well, the possibility of bidirectional decoding offers a chance to increase the likelihood of explored paths. We have developed three successive algorithms that offer a good decrement in the overall complexity, and mainly in the most complex decoding case, while giving near-maximum-likelihood performance. This is important since it determines the maximum buffer size necessary in the decoder