Advanced Joint Transceiver Design for Block-Diagonal Geometric-Mean-Decomposition-Based Multiuser MIMO Systems

In this paper, we propose an advanced joint transceiver design for block-diagonal geometric-mean-decomposition (BD-GMD) based multiuser multiple-input-multiple-output (MIMO) systems. First, we use the lattice reduction (LR) method to design the BD-GMD-based advanced detection and precoding for an uplink and a downlink, respectively. Then, we exploit the vector perturbation (VP) technique to further improve the system performance of the multiuser downlink. To directly reduce the high complexity of VP by a sphere encoder, we provide an LR-based sphere encoder and LR-based approximations for perturbation symbols. Performance and complexity analyses are given to show the advantages of the proposed schemes. Particularly, the diversity-gain analysis shows some insights of the existing and proposed schemes. Simulation results verify the performance improvement as well as the theoretical analysis.