5G OTA/massive MIMO testing

Rohde & Schwarz offers comprehensive over-the-air (OTA) test solutions to pave the way for mmWave and massive MIMO antennas.

5G networks will need to offer more capacity and flexibility while lowering system operating expenses (OPEX). The simplest method to increase capacity would be to increase the number of base stations in the network. However, since this method involves high costs for real estate and energy consumption, it will be met with only limited acceptance. A more promising method is to use a high number of TX and RX antenna elements with amplitude and phase control. These are referred to as massive MIMO systems. There are various ways to operate such systems. They can be used to allow multiple precoded data streams via spatial multiplexing or to increase the gain via beamforming, or a combination of the two.

Rohde Schwarz Wireless Communications 5G Massive MIMO

E-field visualization and accurate OTA beam pattern measurement for AAS

E-field visualization and OTA beam pattern measurement

In the established sub-6 GHz frequency spectrum, base stations typically apply a high number of TX/RX antenna elements to serve multiple users with parallel data streams. This is known as multi-user MIMO (MU-MIMO). In contrast, the high path loss attenuation in the cmWave and mmWave spectrum requires high antenna gains, which are achieved by applying dynamic beamforming. Targeting individual UEs with signals assigned specifically to them significantly reduces energy consumption. Both MU-MIMO and beamforming increase the cell capacity without the need for additional base stations.

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Rohde & Schwarz wireless communications 5G architecture massive mimo active antenna system

Typical architecture of a massive MIMO active antenna system

Your 5G test challenges

When designing a massive MIMO active antenna system, development engineers face new challenges that include phase shifter tolerances, thermal effects of the power amplifiers (PA) and frequency drifts between modules, which affect the desired beam patterns. In an active antenna system, the transceiver frontends are integrated together with the antenna array, which means that traditional RF output ports are no longer accessible. In addition, a fiber interface replaces the traditional RF input ports for digital I/Q data. Consequently, over-the-air (OTA) testing becomes the default use case for massive MIMO systems, also to model the spatial properties of the propagation channel. Due to the different sizes of massive MIMO systems, testing in far-field conditions requires a variety of shielding environments.

Benefits of Rohde & Schwarz 5G test solutions

Rohde & Schwarz offers a comprehensive one-stop test solution portfolio for performing OTA measurements on 5G modules, devices and massive MIMO active antenna systems operating at traditional cellular frequencies below 6 GHz and in the cmWave and mmWave frequency ranges:

Turnkey test solutions including all required test and measurement instruments, antennas and accessories
cmWave and mmWave user device testing: scalable and portable R&S®ATS1000 shielded chamber including an integrated high-precision conical cut positioner and an optional laser for proper path loss calibration and accurate DUT alignment
Optional thermal solution that fits into R&S®ATS1000 for testing mobile devices under extreme temperature conditions to investigate thermal effects in the –20 °C to +85 °C temperature range using an external thermal stream
Accurate and fast sub-6 GHz massive MIMO base station testing: the extremely compact, innovative R&S®PWC200 plane wave converter generates a 3D spherical quiet zone of 1 m in diameter at a distance of only 1.5 m for realtime radiated power and transceiver measurements
Broad range of standardized wireless performance test chambers (WPTC) of various dimensions that address customer site requirements in cooperation with -Albatross Projects
Adding the R&S®ZVA four-port network analyzer and R&S®AMS32 measurement and control software allows 2D/3D pattern characterization, including near-field (NF) to far-field (FF) transformation
The combination of the R&S®SMW200A vector signal generator and R&S®FSW spectrum and signal analyzer allows full RF transceiver characterization, for example by using modulated signals to measure key performance metrics such as EVM
Optional R&S®OSP open switch and control platform simplifies interconnections within the system
Additional R&S®NRPM OTA power sensors enable power measurements at dedicated positions for e.g. beam steering testing"

Learn more about over-the-air testing

Webinar: Multiple directions of arrival using CATR OTA measurements

Join and learn about a novel method using multiple compact antenna test range (CATR) reflectors to perform simultaneous multiple angle measurements for 5G devices that are capable of beamforming in the mmWave frequency range.

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White paper: Over-the-Air RF conformance measurements on 5G NR devices

Read this white paper to learn more on the technical background for over-the-air (OTA) testing on 5G NR devices. Focusing on RF conformance aspects and UEs, the paper examines the requirementsdescribed in the technical specifications.

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Get ready for over-the-air (OTA) testing!

Download your free white paper “Demystifying over-the-air (OTA) testing – important antenna parameters, test system setup and calibration”.

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Download your free massive MIMO eGuide

Get a concise overview of what massive MIMO is all about, its biggest challenges and how to create far-field conditions at short distances to achieve a compact test setup.