How conformance shapes the 5G future of Vietnam

Lawrence Liu, Asia-Pacific general manager at electronics testing and measurement equipment and software manufacturer Keysight Technologies

Are we at the tipping point? You may hear some industry experts say standards are complete, but are they really?

5G New Radio (NR) was designed to be the global standard for the air interface of the 5G network. But will 5G NR products live up to consumer expectations? And if they do not, what is the impact on the industry and on product development? Let us explore where we are in 5G NR rollout with respect to required tests, challenges, and risks.

5G products and components including modems, antennas, sub-systems, and fully assembled end-user devices, require testing throughout the ecosystem. All of these devices and base stations will follow a similar testing workflow, of research and development, design validation, conformance, and device-acceptance testing. With many rules and regulations to follow to bring a mobile wireless communications product to market, testing is performed throughout a product’s lifecycle to ensure the end product meets Third Generation Partnership Project (3GPP) specifications and delivers the quality of service mobile operators aim to deliver to their customers.

Conformance tests are mandatory to release a device. They involve connecting a device to a wireless test system and performing the following 3GPP tests: radio frequency transmission and reception performance – minimum level of signal quality; demodulation – data throughput performance; radio resource management – initial access, handover, and mobility; and signalling – upper layer signalling procedures. Conformance tests are performed by third-party test labs to determine if a product is compliant. These tests are expensive, driving most companies to conduct their own pre-conformance tests to ensure their product will successfully pass these tests at independent laboratories.

New features, new challenges

5G NR introduces many new features that increase test complexity. Higher frequency operation, wider channel bandwidths, flexible waveform structure, and the increasing number of test cases that need to be validated all impact test design. It needs to accommodate many different use scenarios from very high throughput to low packet size, to very low latencies with high reliability. To support these, the 5G NR physical layer was defined with high flexibility, changing the way signals are created and operate.

In addition, there are seven different system architecture options and dual connectivity with 4G LTE that must be implemented. Testing must be performed for the many different use cases. Furthermore, it involves signalling and RF tests, including testing for full end-to-end performance with real-world impairments like excessive path loss, multi-path fading, and delay spread.

Testing these functions requires an over-the-air (OTA) test solution that can emulate base station protocols and channel conditions to understand true performance.

Meanwhile, the active nature of 5G beam steering and beam forming requires validation in an OTA setting. Key aspects such as antenna gain, side lobe, and null depth for the full range of 5G frequencies and bandwidths can have a major impact on system performance. In particular, 3D antenna beam measurements introduce many complexities.

While increased path loss and signal impairments were not an issue at 6 GHz and below, such phenomena are problematic at extremely high frequencies. Thus, test solutions for such frequencies not only need to accommodate higher frequencies with wider channel bandwidths but also address higher path loss. To that end, a test solution must have adequate signal-to-noise ratio to accurately detect and demodulate 5G signals.

Risks and consequences

How will the 5G NR radio access network perform? Will devices connect flawlessly from one base station to another and provide dual connectivity with 4G LTE? Will devices, base stations, and the complete ecosystem deliver on key performance indicators such as 20 Gbps in the downlink for UHD video streaming? Will they provide the expected low latency for driverless automobiles? Will they deliver the high reliability required for no-fail applications? These are just a few of the questions keeping design engineers up at night.

Low-quality products can cause higher repair costs, return rates, and result in lower market share and shrinking profits for a company.

A product introduced with an underperforming operation model, inefficient process, or expensive tests can also decrease production output or lead to low product quality, and have dire consequences on reputation and sales for original equipment manufacturers across industries, semiconductors, communications, automotives, or healthcare. Incomplete and evolving targets are putting significant pressure on developers who need to ensure that their designs and tests are flexible enough to handle future requirements. Designs and test systems will need to scale to new higher frequency bands, potentially with higher channel bandwidths, and implement lower latency and co-existence with unlicensed bands.

Most vendors working on 5G NR are planning to phase in 5G capabilities The real test for 5G products is further down the road, when critical applications with higher consequences are introduced. Companies developing 5G products will have to engage with a test partner to working with leaders across the wireless ecosystem who has already faced most of the difficulties involved in verifying both compliance and capability.