MMSE Based Greedy Eigenmode Selection for AF MIMO Relay Channels

In this paper, the authors consider a dual-hop Amplify-and-Forward (AF) Multiple-Input Multiple-Output (MIMO) relay system, where there is one source, one destination and K relay nodes. They propose a Minimum Mean Squared Error (MMSE)- based eigen-mode selection algorithm to choose several relay nodes to minimize MSE. They use eigen-mode-based definitions for the equivalent backward and forward channels, and extend the present MMSE-based selection scheme to multiple power amplifier configuration. According to the closed form expression of MSE, they iteratively select eigen-mode pairs to minimize the MSE. Simulation results show that their scheme outperforms the existing ones.