Soft-decision-and-forward protocol for cooperative communication networks based on Alamouti code

Abstract

A cooperative protocol called soft-decision-and-forward (SDF) is introduced. SDF protocol exploits the soft decision values of the received signal at the relay node. Alamouti code is used for orthogonal transmission and distributed space-time codes are designed for non-orthogonal transmission. The maximum likelihood decoders with low decoding complexity are proposed. From simulations, it can be seen that SDF protocol outperforms AF protocol.