MMSE-DFE Based MIMO Relay System with Correlated Fading Channel

Abstract—We consider a practical dual-hop nonregenerative multiple-input multiple-output (MIMO) relay system, where the relay node only knows the correlation matrix of the relay-destination channel. A nonlinear minimal mean-squared error (MMSE)-based decision feedback equalizer (DFE) is used at the destination node to retrieve the source signals. We derive the structure of statistically optimal source and relay precoding matrices to minimize a class of objective functions which are multiplicatively Schur-convex with respect to the diagonal ele-ments of the MSE matrix. Simulation results demonstrate that the proposed algorithm has a very close performance compared to MIMO relay system with full channel knowledge at the relay node, and thus is very useful for practical relay systems. Index Terms—Channel correlation, DFE, MIMO relay, MMSE. I