A cooperative relaying protocol without reducing spectral efficiency for wireless communications systems

Cooperative relaying (CR) allows single-antenna terminals to gain some benefits of transmit diversity without the need for physical antenna arrays. CR (with one relay) includes two phases where the first one is for the transmission of the source and the second for the relaying of the relay, thus significantly reducing spectral efficiency. In this paper, we propose a novel CR protocol without any loss of spectral efficiency. Additionally, while existing protocols pay for a worse performance than direct transmission in the low SNR regime (which is of interest in many cellular networks, e.g. UMTS), ours is better over the whole range of SNR.