On APP-decoding using BEAST
Irina E. Bocharova, Rolf Johannesson, Boris D. Kudryashov, Matea Lončar · 2004
Good approximations of code-symbol a-posteriori probabilities (APPs) are obtained using a list of the most likely codewords, instead of the whole code-book. This list is found by Bidirectional Efficient Algorithm for Searching code Trees (BEAST), whose complexity is shown to be lower than of the known trellis-based algorithms.