Abstract-Radiated testing of massive multiple-input-multipleoutput (MIMO) devices in fading radio channel conditions is expected to be essential in development of the fifth generation (5G) base stations (BS) and user equipment (UE) operating at or close to the millimetre wave (mm-wave) frequencies. In this paper we present a setup upgrading the multi-probe anechoic chamber based system designed originally for 4G UE. We describe methods for mapping radio channel models onto the probe configuration and discuss the differences to the former 4G case. We also propose metrics to assess the accuracy of the test setup and find key design parameters by simulations. The results with the utilized channel models indicate that at 28 GHz up to 16 × 16 planar arrays can be tested with range length of one meter and with at minimum eight active dual polarized probes.

Accurate characterization of spatial multipath channels at millimeter wave bands has gained significant interest both in industry and academia. A channel measurement was conducted at three different frequency bands, i.e., 2 − 4, 14 − 16, and 28 − 30 GHz in a line-of-sight (LOS) and an obstructed-LOS (O-LOS) scenarios in an empty room environment. A vector network analyzer connected to a virtual uniform circular array and to a rotational directional horn antenna was used in the measurements, respectively. Angle-of-arrivals and delay-of-arrivals of the multipath components were obtained from the measurements for the three frequency bands. Room electromagnetic properties for the three different frequencies at different propagation scenarios were investigated as well.

This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on channel spatial characteristics emulation. A novel technique to obtain optimum power weights for the OTA probes based on convex optimization is proposed. The proposed technique emulates spatial correlation as well as introduces constraints on the maximum deviation between the target power azimuth spectrum (PAS) and the emulated PAS in terms of mean angle of arrival (AoA) and azimuth spread (AS). Simulation results show that the proposed emulation technique present better performance compared with existing techniques in the literature. This improvement is further demonstrated by measurement results in a practical MIMO OTA setup.

With the severe spectrum congestion of sub-6GHz cellular systems, large-scale antenna systems in the millimeter-wave (mmWave) bands can potentially meet the high data rate envisioned for fifth generation (5G) communications. Performance evaluation of antenna systems is an essential step in the product design and development stage. However, conventional cable conducted test methods are not applicable for mmWave devices. There is a strong need for over-the-air (OTA) radiated methods, where mmWave device performance can be evaluated in a reliable, repeatable, and feasible way in laboratory conditions. In this article, radiated testing methods are reviewed, with a focus on their principle and applicability for beam steerable mmWave devices. To explore the spatial sparsity of mmWave channel profiles, a cost-effective simplified 3D sectored multi-probe anechoic chamber (MPAC) system with an OTA antenna selection scheme is proposed. This setup is suitable for evaluation of beam-steerable devices, including both base station (BS) and user equipment (UE) devices. The requirements for the test system design are analyzed, including the measurement range, number of OTA antennas, number of active OTA antennas and amount of channel emulator resource. Finally, several metrics to validate system performance are described for evaluation of mmWave devices.

Conventional conductive method, where antennas on the device under test (DUT) are disconnected from antenna ports and replaced with radio frequency (RF) coaxial cables, has been dominantly utilized in industry to evaluate multiple-input multiple-output capable terminals. However, direct RF cable connection introduces many practical problems and a radiated method to replace cable connection is highly desirable. Existing wireless cable method relies on the knowledge of a transfer matrix between the channel emulator (CE) output ports and DUT antenna ports, and also requires an anechoic chamber, which might be impractical and expensive. In this paper, a novel wireless cable method is proposed and experimentally validated. By recording the average power (i.e., reference signal received power in the long-term evolution) per DUT antenna port and selecting optimal complex weights at the CE output ports, a wireless cable connection can be achieved. The proposed method can be executed in a small RF shielded anechoic box and offers low system cost, high measurement reliability, and repeatability.