ML decoding of block codes on their tailbiting trellises

A maximum likelihood decoding algorithm is presented for tailbiting trellises for block codes. The algorithm works in two phases. The first phase is a Viterbi decoding algorithm on the tailbiting trellis, while the second uses the A* algorithm adapted for application in this context. Results of simulations on tailbiting trellises for some block codes, indicate that this decoding algorithm is quite fast.