Analysis of computer simulated and field experimental results in multiuser MIMO system considering errors of CSI feedback under multipath fading environments

Abstract

In this paper, the transmission performance considering an error of channel state information (CSI) feedback for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment are described. In computer simulation, a downlink MU-MIMO system can be realized by using the block diagonalization algorithm, and each user can receive signals without any signal interference from other users by using the perfect CSI feedback. The bit error ratio performance and channel capacity in accordance with the errors of CSI were simulated in a multipath fading environment. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimental results, it was confirmed that the maximum throughput performance in the downlink had almost the same performance as the simulated throughput when the error of CSI was 30 %.