  In this work, we present a 2x2 near-field multi-input multiple-output (MIMO)
prototype for bit-error-rate (BER) and error vector magnitude (EVM)
measurements in a metal enclosure. The near-field MIMO prototype is developed
using software-defined-radios (SDRs) for over-the-air transmission of QPSK
modulated baseband waveforms. We check the near-field MIMO BER and EVM
measurements in three different scenarios in a highly reflecting metal
enclosure environment. In the first scenario, the line-of-sight (LOS)
communication link is investigated when the mode-stirrer is stationary. In
stationary channel conditions near-field MIMO BER and EVM measurements are
performed. In the second scenario, BER and EVM measurements are performed in
dynamic channel conditions when the mode-stirrer is set to move continuously.
In the third scenario, LOS communication near-field MIMO BER and EVM
measurements are performed in stationary channel conditions but now in the
presence of MIMO interference. In three different scenarios, near-field MIMO
BER and EVM measurements are investigated at different Tx USRP gain values and
in the presence of varying levels of MIMO interference.
