Novel soft symbol estimate and forward scheme in cooperative relaying networks

In this paper, a novel relaying protocol with low computation complexity, named Soft-symbol Estimate and Forward (SEF) scheme is proposed for cooperative relay system. The scheme holds the advantages of two conventional relaying protocols, Amplify-and-Forward (AF) and Decode-and-Forward (DF), keeping all the soft information and obtaining decoding gain. The relay performs SISO decoding and re-encoding, as well as the key point of soft symbol estimate, based on the simple linear combination of A posterior probability of each received symbol in the relay. From the simulation results, the comparisons of various relaying schemes in different cases are depicted. We find that the proposed scheme can obtain a considerable performance gain compared to the other relaying protocols in most cases.