Institute of Electrical & Electronic Engineers
The authors propose a novel transmission scheme for a relay system that consists of a source, an Amplify-and-Forward (AF) relay, and a destination, which are all multi-antenna nodes and employ beamforming. The proposed scheme is based merely on local channel state information. The source transmits to the relay only when the source finds that the source-destination link will be in outage. In so doing, the proposed scheme lends itself to providing better average spectral efficiency. They derive an exact closed-form expression of the outage probability for Rayleigh fading channels and determine the system diversity gain.