Diagonalized two-way MIMO AF relaying for non-simultaneous traffic in cellular systems

A novel multiple-input multiple-output (MIMO) channel-diagonalization design is proposed for non-simultaneous two-way relaying (NS-TWR). Unlike conventional TWR, the base station in NS-TWR serves two different users - a transmit-only user and a receive-only user. The receive-only user experiences back-propagating interference (BI). The proposed design, which uses linear receivers, cancels the BI and diagonalizes the end-to-end MIMO channels. The diagonalized NS-TWR overcomes the restrictive antenna configurations of existing designs and yields substantial sum-rate improvement over them.