Indoor Experiments of Real-Time MU-MIMO with CSI Feedback Scheme for Wireless LAN Systems

This paper presents indoor experimental results on an implemented real-time downlink multiuser multiple-input multiple-output (DL-MU-MIMO) transceiver with a channel state information (CSI) feedback scheme for next generation wireless LAN systems. Estimated CSI is used at the access point (AP) transmitter to calculate transmit beamforming weight for DL-MU-MIMO transmission. A CSI compression scheme using discrete cosine transform (DCT) is proposed to reduce CSI feedback overhead. The transceiver performance is demonstrated and indoor experiments clarify that it is a feasible tool for real-time signal processing that improves system throughput over that of transceiver without a CSI compression scheme with simple digital signal processing of single-antenna stations (STAs).