Selection cooperation with transparent amplify-and-forward relaying in MIMO relay channels

In this paper, we consider a single-relay cooperative scenario, where the source, relay, and destination terminals are equipped with multiple transmit and receive antennas. We focus on the so-called transparent Amplify-and-Forward (T-AaF) for MIMO relay channels, in which the relay requires neither channel state information (CSI) nor synchronization of symbols or carrier. Specifically, we propose and analyze new selection schemes where the relay, based on the received signal energies, select the "best" received signals on the S → R hop and retransmits them to the destination terminal with either repetitive or selective transmission. Through the derivation of pairwise error probability (PEP) expressions and asymptotic order of diversity (AOD) analysis, we demonstrate that the proposed selection schemes maintain full diversity order. Furthermore, we show that selective transmission on R → D hop has better performance, better throughput, and significantly better energy efficiency than repetitive transmission.