Non-recursive max* operator with reduced implementation complexity for turbo decoding

In this study, the authors deal with the problem of how to effectively approximate the max* operator when having n>2 input values, with the aim of reducing implementation complexity of conventional Log-MAP turbo decoders. They show that, contrary to previous approaches, it is not necessary to apply the max* operator recursively over pairs of values. Instead, a simple, yet effective, solution for the max* operator is revealed having the advantage of being in non-recursive form and thus, requiring less computational effort. Hardware synthesis results for practical turbo decoders have shown implementation savings for the proposed method against the most recent published efficient turbo decoding algorithms by providing near optimal bit error rate (BER) performance.