315 research outputs found
Virtual Drive Testing Over-The-Air for Vehicular Communications
Multiple-input multiple-output (MIMO) over-the-air (OTA) testing is a standardized procedure to evaluate the performance of MIMO-capable devices such as mobile phones and laptops. With the growth of the vehicle-to-everything (V2X) service, the need for vehicular communication testing is expected to increase significantly. The so-called multi-probe anechoic chamber (MPAC) setup is standardized for MIMO OTA testing. Typically, a test zone of 0.85 wavelength in diameter can be achieved with an 8-probe MPAC setup, which can encompass device-under-test (DUT) of small form factors. However, a test zone of this size may not be large enough to encompass DUTs such as cars. In this article, the sufficient number of OTA probes for the MPAC setup for car testing is investigated with respect to the emulation accuracy. Our investigation shows that the effective antenna distance of the DUT is more critical than its physical dimensions to determine the required number of OTA probes. In addition, throughput measurements are performed under the standard SCME UMa and UMi channel models with the 8-probe MPAC setup and the wireless cable setup, i.e. another standardized testing setup. The results show reasonably good agreement between the two setups for MIMO OTA testing with cars under the standard channel models
Dynamic mmWave Channel Emulation in a Cost-Effective MPAC with Dominant-Cluster Concept
Millimeter-Wave (mmWave) massive multiple-input multiple-output (MIMO) has
been considered as a key enabler for the fifth-generation (5G) communications.
It is essential to design and test mmWave 5G devices under various realistic
scenarios, since the radio propagation channels pose intrinsic limitations on
the performance. This requires emulating realistic dynamic mmWave channels in a
reproducible manner in laboratories, which is the goal of this paper. In this
contribution, we firstly illustrate the dominant-cluster(s) concept, where the
non-dominant clusters in the mmWave channels are pruned, for mmWave 5G devices
applying massive MIMO beamforming. This demonstrates the importance and
necessity to accurately emulate the mmWave channels at a cluster level rather
than the composite-channel level. Thus, an over-the-air (OTA) emulation
strategy for dynamic mmWave channels is proposed based on the concept of
dominant-cluster(s) in a sectored multiprobe anechoic chamber (SMPAC). The key
design parameters including the probe number and the angular spacing of probes
are investigated through comprehensive simulations. A cost-effective
switchcircuit is also designed for this purpose and validated in the
simulation. Furthermore, a dynamic mmWave channel measured in an indoor
scenario at 28-30 GHz is presented, where the proposed emulation strategy is
also validated by reproducing the measured reality.Comment: Accepted by IEEE Transactions on Antennas and Propagatio
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