Auto-calibrated MIMO-OFDM channel sounder for 3D spatial channel characterization

This paper presents an improved test-bed designed for analyzing the spatial behaviour of wideband indoor channels using MIMO-OFDM systems. A 3D antenna positioning system (3-DAPS) is specifically designed for obtaining 3D spatial data. Also, it allows carrying out some measurements in the range of correlation distance where fading of the radio channel link is significant for indoor scenarios. Special emphasize is made on the RF calibration module, which is designed to track the frequency response of all RF chain of transmitter and receiver and apply those responses to the channel measurements. The average of the pseudo-spectrum MUSIC over all frequencies improves the resolution of the spatial spectrum giving clear peaks where a signal source is and smoothing fake peaks coming from scatters.