A Minimum Mean-Square Error Criterion Based Nonlinear Joint Transmitter-Receiver Processing Algorithm for the Downlink of Multi-User MIMO Systems

This paper focuses on signal processing algorithms for the downlink of multi-user multiple-input multiple-output (MIMO) systems with multiple antenna mobiles. A novel nonlinear joint transmitter-receiver processing algorithm is proposed. In this algorithm, linear receiver processing is applied at each mobile, while nonlinear Tomlinson-Harashima precoding (THP) is applied at the base station. Closed-form solution of the transmitter and receiver processing matrices is found based on the minimum mean-square error (MMSE) criterion. For this algorithm, it is found that better performance can be achieved by suitably ordering the channel matrices of different mobiles, and the "best-first" ordering method is proposed to perform the ordering. Simulation is used to show the advantages of the proposed algorithm and the "best-first" ordering method