Evaluation Engineering - 23

This eliminates the time waste of moving discretely from point to point."
Nichols at Keysight also commented on
OTA test, noting that 100% of mmWave
test cases are OTA. "OTA testing is not
unique to 5G, but there are parts that are
particularly novel," he said, citing the directional nature of the radio transmission. "The concept of managing a beam
that points from the transmitter to the
receiver and focusing the receiver on
that beam is new to 5G," he said. "What
makes this extraordinary is that one of
the radio transceivers involved is mobile
and can be moved to any location and any
orientation with the radio system making every possible effort to maintain the
link. Testing this involves a complex set
of measurements that validate the flexibility of the spherical coverage of the UE
for both Tx and Rx-and all of these are
calibrated over-the-air measurements.
The standards for managing mobility
for mmWave are not yet complete, so it
is easy to assume that this will continue
to present challenges."
Nichols also commented on the company's FieldFox portable analyzer for
5G, satellite-communications, signalmonitoring, and electronic-warfare applications. "Complex beam sweeping technologies used with radar and EW systems,
as well as with 5G control channels, will
require wider bandwidths and real-time
spectrum-analysis tools to capture these
intermittent and elusive signals," he said.
"FieldFox can connect to 89600 VSA software to demodulate 5G NR and LTE-A
signals up to 100 MHz or easily switch to
over-the-air (OTA) measurements for 5G
and 4G LTE to verify gNB performance."
Roessler at Rohde & Schwarz noted
that 5G requires an increasing amount of
OTA testing. Rohde & Schwarz launched
three new OTA solutions based on CATR
technology: the R&S ATS800B benchtop
solution, the R&S ATS800R rack solution,
and the R&S ATS1800C 5G NR mmWave
test chamber. "All these OTA solutions
feature a high-precision CATR reflector
to generate a big useable measurement
area (the so-called quiet zone, QZ) in a
very compact setup," he said. "The R&S
ATS800B and R&S ATS800R provide a
20-cm QZ whereas the R&S ATS1800C

offers a 30-cm QZ, which complies with
3GPP RF conformance test requirements.
The portable compact chamber solution
provides very high shielding efficiency
and features a 3D positioner that can
even move more heavy devices up to 8 kg."
Douglas at Spirent emphasized digitaltwin applications. "The 5G digital twin
is an emulated software replica of the
physical network, allowing continuous
prototyping, modeling, and research," he
said. "As 5G moves us from being a physical network to a living system, the digital
twin is an ideal solution. The digital twin
consists of multiple emulation, traffic, and
signal-generation functions working in
harmony to provide a virtual software
version of the 5G network."

Investment protection
The move to 5G has implications for investment protection. Adnan Khan, senior
business development manager for wireless products at Anritsu, noted that the
company's existing customers can repurpose their 4G assets towards 5G, using, for
example, Anritsu's MT8821C radio communication analyzer as an LTE anchor.
"This also gives customers the option of
using a GUI they are familiar with for
testing," he said. "Also, for conformance
systems, Anritsu is able to use many 4G
solutions in 5G applications."
Nichols at Keysight noted that in some
cases equipment used to test 4G can
test 5G, possibly with software updates.
In other cases, test equipment must be
completely rebuilt to address mmWave
frequencies and OTA requirements.
Keysight, he said, works on line extensions as well as commercial technology
refresh programs. "Of course, we have to
ensure that new platforms can manage
the demands of not just the new technology, but also that of the legacy and of the
interaction between the generations," he
said. "In the case of 5G NSA Core testing,
we have evolved our test solution such that
our customers can seamlessly use all 4G
functionality they have been using without change. In this case, our customers'
investments are protected with 100% reusability. 5G SA core testing brings a new
architecture and a new test paradigm, but
even in this case we expect to be able to

provide our customers with 'fallback'
capabilities such that their validation of
standalone 5G services is not conducted
at the expense of 4G validation."
Roessler at Rohde & Schwarz cited the
company's widely used R&S CMW500
platform. "The initial roll-out of 5G is
based on non-standalone (NSA) mode
where an LTE anchor is required for the
exchange of control and signaling information," he said. "Therefore, it was evident
to Rohde & Schwarz to save our customers' investment into the R&S CMW500
for 4G LTE testing and reuse the platform
to provide this anchor functionality. The
R&S CMX500 uses an advanced hardware
design concept and intelligence unified
web-based graphical user interface to
make it the platform to test 5G for decades to come and beyond."
Douglas at Spirent said he doesn't see
the need for 4G test and measurement
diminishing in the short to medium
term due to four industry trends. "First,
many CSPs are aggressively building out
underlay LTE-A Pro networks alongside
5G for 'coverage and fallback' to guarantee customers a premium experience
and look to quickly close and refarm 3G,"
he said. "Second, many Tier 2 CSPs will
stay with 5G evolution (NSA) utilizing the
4G Core (vEPC) for a protracted period.
Third, the growth of private networks will
initially be via LTE evolving towards 5G
from 2022 on. And fourth, in automotive,
C-V2X will first harness LTE before evolving to 5G from 2022 on." Consequently,
"4G test systems will still be critical," he
said. "Customers are asking Spirent to
help create a future-proof pathway for
test tools to evolve to 5G as needed. To
provide this pathway, Spirent has been
developing many of its systems to support
software-defined architectures, virtualization, and cloud-native micro-services.
In addition, our recent partnership with
National Instruments to use their industry leading SDR to underpin our radio test
systems benefits customers from futureproofed investment."
REFERENCE

1. Nelson, Rick, "Innovations from
semiconductors to digital twins drive 5G," EEEvaluation Engineering, December 2019, p. 6.

JANUARY 2020 EVALUATIONENGINEERING.COM

http://www.EVALUATIONENGINEERING.COM

Evaluation Engineering

Table of Contents for the Digital Edition of Evaluation Engineering