Symbol by symbol APP decoding with a generalized Viterbi decoder

Abstract

We discuss a s y m b o l b y symbol APP decoding algorithm that only uses forward recursions. Originally, this algorithm was described for o p t i m u m soft-output detection for channels w i t h IS1 and is called t h e o p t i m u m soft-output algorithm (OSA) [l]. We have proven the convergence of the OSA and show t h a t it is a generalization of the Viterbi algorithm.