Antenna selection in the full-duplex multi-antenna relay channel

We consider the problem of antenna selection (AS) in full duplex amplify-and-forward relaying. We assume a basic relay system where the source, the relay and the destination, all equipped with multiple antennas. For this full-duplex relay system, we investigate different AS schemes to select a single transmit antenna at both the source and the relay, respectively, as well as a single receive antenna at both the relay and the destination, respectively. To facilitate comparison, exact outage probability expressions and asymptotic approximations of these AS schemes are derived. In order to eliminate the zero-diversity behavior associated with the full-duplex operation, we also propose a simple power allocation (PA) scheme at the relay. In addition, the optimal value of the PA parameter is analytically derived for the considered AS schemes.