Multiple Relay Nodes Selection Scheme with Zero Forcing Weighting Matrix in MIMO Relay Networks

The paper considers MIMO relay networks where a source node transmits the signals to a destination node through multiple relay nodes, each of which is equipped with multiple antennas. As shown by previous studies, using multiple relay nodes to forward the signals can improve the performance. The distributed array gain can be achieved at the destination node while maintaining the maximum spatial multiplexing gain when the zero-forcing (ZF) weighting matrices are applied at the relay nodes. However, this relaying scheme cannot obtain the receive array gain simultaneously. To overcome the disadvantage, we propose a novel multiple relay nodes selection scheme based on the criterion of maximizing the minimum received SNR among all antennas at the destination node to enhance the diversity gain and the array gain. Simulation results confirm the superiority of our proposed selection scheme over the conventional ZF MIMO relaying scheme.