X-Duplex Relaying: Adaptive Antenna Configuration

We propose a joint transmission mode and transmit/receive (Tx/Rx) antenna configuration scheme referred to as X-duplex in the relay network with one source, one amplify-and-forward relay, and one destination. The relay is equipped with two antennas, each of which is capable of reception and transmission. In the proposed scheme, the relay adaptively selects its Tx and Rx antenna, operating in either full-duplex or half-duplex mode. The proposed scheme is based on minimizing the symbol error rate (SER) of the relay system. The asymptotic expressions of the cumulative distribution function for the end-to-end signal to interference plus noise ratio, average SER and diversity order are derived and validated by simulations. Results show the X-duplex scheme achieves additional spatial diversity, reduces the performance floor at high SNR, and improves the system performance.National 863 project [2015AA01A709 5G]; National Nature Science Foundation of China [U1301255, 61461136002, 61371073]; ARC [DP150104019, FT120100487]; NSFC [61671183]SCI(E)ARTICLE51083-10862