Standards-compliant Testing Shaping up the Path for 5G Innovation

By Kashif Hussain, Wireless Solutions Director at VIAVI Solutions.

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5G will be a key enabler of technological innovation. It would render the perfect blend of speed, ultra-low latency, capacity, efficiency and throughput to deploy, orchestrate and automate diverse networks and devices.

5G technology is driving major changes across the entire network — from highly flexible radio access network (RAN) architecture and 3D beamforming active antennas, to software-defined network components — with stringent timing and latency requirements. The combination of new infrastructure features and functions, such as millimeter wave (mmWave) utilization and massive MIMO, provides a pathway to incredible performance enhancements. Yet these expected enhancements will rely on multiple elements performing seamlessly in tandem, introducing much greater complexity than previous generations.

Mission-critical applications will demand a network which cannot fail. Ensuring network quality will be at the core of deployment to prevent dissatisfied end users, churn and loss of market share.

Breaking it Down

The added complexity introduced by new 5G functionality is posing challenges for network equipment manufacturers (NEMs) and communication services providers (CSPs) alike. Moreover, these complications are further compounded by the adoption of disaggregated architectures in which integrated hardware and software are separated and broken down into functional components. As CSPs seek to improve service agility and lower costs, they are increasingly moving away from proprietary network equipment, instead using common off-the-shelf components. This raises the stakes for interoperability and performance, since no single vendor is responsible for validating and verifying the entire system.

As such, standards compliance takes on an increasingly crucial role to ensure functionality and interoperability. Likewise, standards are key to developing accurate 5G test models, leading to more harmonized test practices and empowering faster 5G network development and deployment. Service providers and NEMs need to understand and embrace standards-compliant testing methods to ensure the smoothest path forward for 5G innovation.

However, a key roadblock slowing down 5G roll-outs is the challenge of developing products against changing and maturing 3GPP specifications. Today, the earliest 5G deployments are based on non-stand-alone (NSA) configurations, where existing 4G infrastructure is used, although radios will be capable of providing services to 5G-capable devices as they are introduced. In this initial phase of 5G deployment, the focus is on enhanced mobile broadband (eMBB) service to provide increased data bandwidth and connection reliability. Unlike in LTE networks, 5G new radio (NR) will support higher frequency operation from day one. Frequency range one (FR1) overlaps and extends 4G LTE frequencies, operating from 450 MHz to 6 GHz, whereas frequency range two (FR2) operates at a much higher frequency range and will support up to 52.6 GHz.

Just as we saw with previous generations, 5G networks will evolve across multiple 3GPP releases. Therefore, it’s vital to have a controllable and repeatable test environment that helps implement the latest standards and simplifies the 5G development lifecycle, in order to ensure that network equipment deployed in the field is protected and customer experience is not compromised.

Conforming to Norms

It’s important to recognize the complexity of conformance testing necessary for devices and base stations before they’re released to the marketplace. Conformance tests are important for developing a baseline of functionality in user equipment (UEs) and base stations, as well as validating transmitter and receiver characteristics and performance. Radio resource management (RMM) and protocol testing are needed for devices, while radio frequency (RF) parameters are used as a baseline to test base stations.

Meanwhile, conformance testing for UEs depends upon radio access, demodulation and signaling tests, as well as validation by certification organizations to ensure they comply to the latest 3GPP specifications. Yet, the 3GPP RAN working committee defines the conformance goals, which are not yet complete for 5G NR.

A number of other standards bodies also are contributing significantly in this area. The International Telecommunications Union (ITU) and the International Mobile Telecommunications (IMT) group created IMT-2020, which has three primary use cases for 5G NR: eMBB; ultra-reliable low latency communications (URLLC); and massive machine-type communications (mMTC).

Performing Above and Beyond

Deploying and supporting complex 5G network architecture will not be a trivial exercise. 5G NR will introduce flexible spectrum usage with scalable numerology, dynamic TDD, massive MIMO and beamforming — all of which will introduce greater challenges in the field for RF engineers to validate, test and optimize the 5G network. Time-to-market and network quality will be largely dependent on the rigor of test and measurement before, during and after deployment.

A key factor to consider when testing 5G is how to assure quality of experience (QoE) for the end user. Unlike with previous generations, however, this requires the understanding that in many cases, the end user on 5G networks will be machines, rather than humans. This means that current methodologies for testing and measuring voice, video and data quality to end users need to be expanded to include mMTC and artificial intelligence (AI).

The three primary use cases identified by IMT-2020 – eMBB, URLLC and mMTC – also drive the need for different ways to measure QoE, especially in the RAN. Expanded test methodologies are needed that include new parameters that incorporate higher frequencies and wider bandwidths, accounting for machine-to-machine communications.

As 5G networks grow to support applications like connected cars, network performance will become absolutely crucial. Delay, jitter and other network issues can literally have disastrous results, so testing of 5G QoE needs to be verifiably traced and transparent to certified international standards bodies, as opposed to proprietary NEM specifications or techniques.

Work in Progress

Given the enormous frequency range and high-bandwidth services inherent to 5G technology, standardization of best practices will continue to progress as the technology, tools and applications develop. Without question, there remains a great deal to be done before standards bodies will finalize their work on 5G, and both service providers and vendors are diligently working with industry organizations to develop strategies for the long-term success of 5G networks. The reality is that standards bodies play a vital role in providing a neutral place in the ecosystem, including test and measurement vendors, to collaborate and ensure that mission-critical applications on 5G networks are developed, built and deployed safely and securely for individuals, communities and enterprises.