Novel Cooperative Relaying Network Scheme with Exchange Communication and Distributed Transmit Beamforming

In this paper, we propose a novel scheme of cooperative relaying network based on data exchange between relays before forwarding it to destination. This inter-relay data exchange step is done during an additional middle-slot in order to enhance the transmit signals from relays to the destination. To reduce the propagation errors between relays as well as the required sum total transmit power for relays during this data exchange, only the relay possessing the highest SNR is engaged into exchanging data by forwarding its received signal to the other relays. As for the remaining non-selected relays, i.e., with low SNR, the transmitted signal is estimated by using both signals received separately at different time slots (i.e., 1 and 2 slot) from source and the ‘best’ relay, respectively, emulating 2element virtual antenna array where appropriate weights for the antenna array are developed. In addition, we investigate distributed transmit beamforming and MRC at the relays and the destination, respectively, to combine coherently the received signals. At the relay optimal location and at low SNR condition, the proposed method has significant better outage behaviour and average throughput than conventional methods using one or two time slots for transmission. Keywords-component; Cooperative relaying network, Adaptive antenna array, Transmit beamforming, MRC.