A simple cooperative extension to wireless relaying

In this paper, we propose and analyze a simple protocol that simultaneously exploits two potentials offered by wireless relay systems: diversity gains and pathloss savings. An intermediate decode-and-forward relay assists transmission from source to destination, and the destination combines the signals it receives from source and relay. The key feature of the proposed system is that the relay node decides independently whether or not to forward information to the destination, thereby minimizing the risk of error propagation while providing truly constructive diversity gains. In combination with pathloss savings, this leads to significant gains over both direct transmission and conventional relaying. The results are obtained from an analysis of the end-to-end bit error rate, which are confirmed by simulation.