5G poses new generation of test challenges

Author : James Kimery, Director of Wireless Research & SDR at National Instruments

05 June 2018

5G will bring a step change in the speed at which we access data via mobile devices. This is great news for consumers, but only scratches the surface of the societal and business benefits that will be felt...

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5G, moreover, will not only impact mobile communications – it will enable our vehicles to safely drive themselves, machines to communicate via the Industrial Internet of Things (IIoT), and even allow remote surgery or disaster relief.

Network capacity will grow to accommodate billions of devices; shorter network response times will enable low-latency remote control; and coverage will improve to allow reliable connection in both rural and densely populated environments.

“Ten years from now, we’re going to look back and recognise that 5G was one of the most important pieces of technology ever deployed,” asserts Patrick Moorhead, president and principal analyst at high tech analyst firm, Moor Insights & Strategy. “It will enable virtually every emerging technology trend that we see today – whether it’s self-driving cars that talk to each other, the ubiquitous connectivity and intelligence of the IoT, or just the most amazing and immersive real-time VR and AR multimedia experiences.”

The road to 5G

The 3GPP standardisation body is furiously marching toward defining 5G – but the real work is just beginning. Companies that specialise in semiconductor, network and cloud infrastructure, software, manufacturing and test technologies must now design, develop, test and deliver solutions that take advantage of these new wireless capabilities. This is no easy task.

5G features new technologies, such as Massive MIMO and mmWave. Both technologies use multiple antennas and beamforming, which is a huge departure from current and previous wireless architectures. 5G also includes new wireless control mechanisms that split the control and data to facilitate the concept of network slicing, which scales the level of service to an individual user device.

In addition, the standards proposed for 5G are considerably more complex than previous 3G and 4G standards. 5G will transform our networks: the industry must therefore transform the way these systems are designed, developed and tested. For algorithm design, simply modelling systems without any real-world validation has not been enough for an idea to advance from concept to production. For test, traditional methods that focus on an individual component will not be able to account for the overall impact on the system.

A platform-based approach

Wireless researchers across the world have quickly discovered that the only path to success is via a platform-based approach to 5G, with software at the core. Nokia introduced the first mmWave 5G prototype at 73 GHz and broke the record for mobile access data rates using mmWave spectrum.

Lund University developed the first Massive MIMO prototype, and researchers at both the University of Bristol and Facebook extended their Massive MIMO prototypes to achieve unprecedented spectrum efficiency milestones.

These system prototypes have already played an important part in the 5G technology evolution. The platform-based design approach used in these examples takes full advantage of software-defined radios (SDRs) to tackle system challenges and reduce time to results.

SDRs for design and prototyping will continue to evolve as the software changes. We can even envision more capable SDRs, with software extending beyond the physical layer to leverage the vast ecosystem of open source software.

This will enable researchers to address both the upper layers and the network to further decrease time to adoption and shatter the siloed approach to design.

5G innovation doesn’t stop at design

Test and measurement solutions will be key in the commercialisation cycle. Test systems must expand beyond the physical layer to quickly and cost-efficiently test these new multi-antenna technologies with controllable/steerable beams. Additionally, these systems must address the new mmWave-capable devices with extremely wide bandwidths.

These test solutions must not only be able to test the important parameters of a device, but also be cost-effective in order for 5G to reach its potential and achieve widespread adoption.

With these characteristics, 5G requires a different approach to test for wireless devices and systems. For example, system-level over-the-air (OTA) test must become standard in the 5G ecosystem. OTA test presents numerous challenges, but perhaps the most daunting pertains to the environment in which the test equipment and the device-under-test (DUT) must coexist. Air is an unpredictable medium, and the channel itself varies over time and environmental conditions. Wireless test engineers must isolate the channel in the OTA scenario and control the device on a per-beam basis, in order to effectively ‘test’ the device.

In addition, companies like Intel have introduced early phased array antenna modules that feature the antenna attached directly to the RF front end to minimise system losses. Because access to the device is limited, the test equipment must step up in frequency to the mmWave bands and characterise key performance metrics beam by beam.

Bandwidth is a consideration in most aspects of RF test, yet the step up in bandwidth from 4G to 5G is particularly severe. A 5G new radio channel could deliver up to 50 times the bandwidth of an LTE channel, so measurement instrumentation will require a commensurate increase in capability. Beyond instrument specification, greater strain will be placed upon the processors, buses and storage within test architectures, in order to transport, store and compute more data – often in real time.

What’s next?

There has been an intense, global focus on researching the early phase of 5G – accelerated by a flexible approach using SDRs. The next step, testing 5G devices, cannot be ignored. Test solution providers must embrace a similar platform-based approach to meet the stringent technical demands and increased device volume that 5G will bring.


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