Test and Measurement Is a Major Hurdle for 5G

New test rigs and strategies are crucial to keeping 5G on track

5G testbed radio rig
Photo: Instituto de Telecomunicações
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Back in June of this year, the component technologies for 5G continued their inexorable march forward with Release 15 of the 5G New Radio specifications. These let equipment manufacturers know the standards network gear must meet to enable 5G networks.

At about the same time, a team of researchers at the Instituto de Telecomunicações (IT) in Portugal published a study in the journal IEEE Access that looked at the equipment that was available at that time to see if they measured up to the demands of 5G networks. In particular, they assessed the capabilities of commercial-off-the-shelf radio frequency (COTS RF) equipment. In these tests, millimeter wave (mmWave) RF front ends did not measure up.

“It has been shown that currently COTS RF front ends do not yet cope fully with 5G requirements,” said Rafael Caldeirinha, a professor at IT, and coauthor of the research, which was further illustrated in a recent IEEE Communication Society webinar now available on demand.

While this research was published at the end of June, the work itself was carried out while the 5G New Radio specifications were still being considered, according to Caldeirinha. Since then manufacturers and vendors have announced varied test and measurement equipment for both signal generation and analysis.

This new test and measurement equipment is poised to raise the level of COTS RF equipment going forward. As previously described [sponsored content], 5G is ushering in a new era in test and measurement.

“For COTS RF equipment, fortunately there has been a plethora of test and measurement equipment made readily available, mostly for generic uses, at the same time as 5G New Radio specifications are just being released,” said Caldeirinha.

This new equipment is based on software-defined radio and with time-domain capabilities coupled to colorful touch screens. Unfortunately, the prices for this equipment remain prohibitively expensive for academia, startups, or even for SMEs (small and medium-sized enterprises), according to Caldeirinha. He believes that if his team had the current state-of-the-art testing rig, it would have made their lives much easier, eliminating the need for additional measurements to cross-reference measurement results in their testing.

Nonetheless, with the 5G New Radio specifications, Caldeirinha says we have entered into a new stage of test and measurement activities that will involve new requirements and procedures.

“Such high-level testing is gradually moving from academia and R&D labs into live networks, with many 5G test beds and measurement trials taking place in many cities across the globe,” Caldeirinha added.

While new test and measurement strategies may pull 5G through its early stages of rollout, Caldeirinha cautions that 5G introduces new technical challenges for testing chipsets and massive multiple-input multiple output (MIMO) antennas, particularly at mmWave frequencies—the radio frequency above 30 gigahertz. He argues that this will require the development of practical and affordable testing methods, spanning the lab, the production line, and deployment networks.

While 5G standards are being established and base stations are well under way, developing effective ways to perform over-the-air (OTA) testing of backbone technologies of 5G like massive MIMO antennas poses many challenges for test facilities.

Caldeirinha added: “The first academic strategies for developing OTA testing are just emerging and there is still a long way to go until affordable test rigs become available.”

Updated 26 November 2018

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