Abstract: Although tremendous progress has been made in the past years on MU-MIMO systems, there still exist a number of problems. We believe that the most important one is related to the channel state information (CSI). In wireless communications “Evaluation of Imperfect CSI Criterion in Multi User MIMO Transceiver System” is still area of concern. Multiple transmit and receive antennas can be used to form multiple-input multiple-output (MIMO) channels to increase the capacity by a factor of the minimum number of transmit and receive antennas. In this paper, we propose a novel joint linear transceiver design for single-user multiple-input, multiple-output (SU-MIMO) systems and Multi-user multiple-input, multiple-output (MU-MIMO) systems employing improper signal constellations. A novel contribution in this paper is to derive a closed-form optimum linear precoder and decoder for both the downlink and uplink MU-MIMO systems with improper modulation by solving the nonconvex optimization problem under total power constraint. The simulation results show that the performance of the proposed design is improved over the previous design.

Keywords: Channel State Information (CSI) ; Minimum Mean Square Error (MMSE) ; Single-User Multiple-Input Multiple-Output (SU-MIMO) ; Multi-User MIMO(MU-MIMO) ; Channel State Information Transmitter (CSIT) ; Channel State Information Receiver (CSIR) ; Signal-to-Noise Ratio (SNR) ; Bit Error Rate (BER).