Over-the-Air Testing of 5G Communication Systems: Validation of the Test Environment in Simple-Sectored Multiprobe Anechoic Chamber Setups

Abstract

XXXXXO ver-the-air (OTA) radiated testing is seen as inevitable for 5G antenna systems. The simple-sectored multiprobe anechoic chamber (SS-MPAC) setup is a potential testing candidate for the evaluation of 5G antenna systems under real-world propagation conditions. Validation of emulated channel models in the practical SS-MPAC setup is essential, since it is important to ensure that the target channel models are correctly emulated. Our objective is to detect the joint-angle delay power profile of the reproduced channels in the SS-MPAC setup. In this article, we discuss two joint-angle delay estimation (JADE) algorithms: 1) an existing algorithm with high computation complexity as the reference method and 2) a novel, low-cost, sequential, 1D algorithm. Both numerical simulations and experimental verification measurements in a preliminary SS-MPAC setup are provided to validate the two discussed algorithms. The proposed sequential 1D search method is demonstrated to be highly accurate and effective and, therefore, is recommended for validation measurements in SS-MPAC setups. Measurement setup and procedures for test-environment validation are considered as well. SS-MPAC SETUPThe demand for ubiquitous, reliable, and high-speed wireless connectivity has been steadily growing. Both massive multipleinput, multiple-output (MIMO) technology and the use of frequencies in the millimeter-wave (mm-wave) range are considered essential to addressing these challenges in the upcoming 5G systems. Radiated OTA testing [i.e., testing without the device under test (DUT) physically connected to the test equipment] has been seen as inevitable for 5G antenna systems [1]- [6]. The 5G antenna systems will be large scale, beam steerable, highly compact, and integrated. It is expected that antennas will be integrated into radio-frequency (RF) transceiver circuits, that is, with no place to probe or put connections. As a result, it will be impractical to use traditional RF connectors between the radio circuit and the antenna due to the integrated design, creating the need for OTA radiated testing.It is important to test DUT performance in real-world propagation scenarios in the laboratory, where the DUT's end-to-end performance (including both radio and baseband parts) can be thoroughly evaluated [7], [8]. The MPAC method has been adopted in the standards for OTA performance testing of 4G LTE terminals due to its ability to test off-the-shelf DUTs, for which all critical parts of the design are evaluated at once [9]- [11]. The MPAC method offers a realistic test condition in which the device can operate normally with the help of a radio channel Validation of the test environment in simple-sectored multiprobe anechoic chamber setups.

Millimeter-Wave New Radio Test Zone Validation for MIMO Over-the-Air Testing

“…However, a ULA is not suitable for measuring channel spatial profiles in the 3D MPAC setups. In [9], a virtual UCA is formed in the test zone to estimate the wide-band PADP of the emulated channels. However, the algorithm was only applicable to the 2D MPAC setup when far field condition is met.…”

“…2) Near-field sequential search algorithm: As detailed in [9], a two-stage sequential search was proposed to reduce the computation complexity associated with angle and delay domain joint search. The same sequential search strategy yet re-designed for the near field condition is applied in this work, as discussed below.…”

“…spatial multiplexing and diversity). It was pointed out in [3], [9], [11] that power angle spectrum (PAS) of the emulated channels are more relevant for 5G NR in FR2. Furthermore, PAS indicates directly where the signal originates, which is more relavant for beam-steerable DUTs.…”

“…• 2D channel models and 2D uniform MPAC setups were defined for 4G MIMO OTA testing, and hence virtual uniform linear array (ULA) [6], [10] and uniform circular array (UCA) [9] were used to sample the test zone. Such virtual array configurations, however, are not sufficient for channel validation in 3D MPAC setups.…”

“…search complexity significantly reduced). Our proposed solution is essentially an extension and improvement of the reference method presented in [9], which was only applicable when far-field condition is met.…”