MMSE based greedy eigenmode selection for AF MIMO relay channels

In this paper, we 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. We propose a minimum mean squared error (MMSE)-based eigenmode selection algorithm to choose several relay nodes to minimize MSE. We use eigenmode-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, we iteratively select eigenmode pairs to minimize the MSE. Simulation results show that our scheme outperforms the existing ones.