Distributed Massive MIMO Channel Measurements in Urban Vehicular Scenario

We present a measurement framework for rapidly time-varying distributed massive multiple-input multiple-output (MIMO) channels. We introduce a custom-built calibration device to facilitate calibration of multiple transceivers as well as a synchronization structure for distributed massive MIMO arrays. Measurements are performed with two transmit and 32 receive antennas in parallel with 115 MHz bandwidth and 1 ms repetition rate at a carrier frequency of 3.52 GHz. The transmit antennas are mounted on a car moving through an urban environment while the receive antennas are placed on the rooftop of a building. We analyze the measured channel characteristics and the singular value spread over time for collocated and distributed receive antenna setups. Our results show that collocated receiver arrays outperform the distributed ones in terms of the singular value spread for the given scenario.