Local CSI Based Selection Beamforming for Amplify-and-Forward MIMO Relay Networks
The authors investigate selection beamforming for a cooperative network that consists of a source, a destination, and two Amplify-and-Forward (AF) relays, which are all equipped with multiple antennas. The transmit and receive beamforming techniques are respectively applied at the source and destination, and the linear processing operator of the selected AF Multiple-Input Multiple-Output (MIMO) relay is optimized. They consider that the source has the instantaneous Channel State Information (CSI) of the channels from the source to relays but no information regarding the CSI of the channels from the relays to the destination. Partial Relay Selection (PRS) is employed, i.e., the source routes its information signal to the relay which offers better first-hop Signal-to-Noise Ratio (SNR).