An Experimental Downlink Multiuser MIMO System with Distributed and Coherently-Coordinated Transmit Antennas

In this paper we present a multiuser MIMO experimental system and the corresponding indoor measurement results that demonstrate power of distributed and coherently-coordinated downlink transmit antennas using zero-forcing (ZF) beamforming. We present experimental performance under different conditions and communication scenarios. We consider different transmit power levels, number of transmit antennas, resolution of channel state information (CSI) quantizer as well as CSI feedback channel data rates. We demonstrate significant gains even in the presence of practical impairments.