5G is shifting toward an Open RAN infrastructure, in which the radio, distributed, and centralized units (O-RU, O-DU, and O-CU) come from a range of vendors, each designed to a set of interoperability standards. The benefits are many, with the technology enabling significant improvements in terms of cost efficiency, performance, and flexibility. By opening the market up to a host of smaller, fast-moving, and innovative market players, technology development can accelerate, with new services and new revenue-generation opportunities emerging for operators.

But ensuring system interoperability from a huge number of vendors requires complex testing procedures, such as system verification, security assessments, certification, and pre-deployment testing. This is beyond the reach of most small and medium-sized enterprises and startups, which prevents these companies from verifying the performance and compliance of their systems. Complexity is still acting as a barrier and discouraging these potential market disruptors from fully engaging in the Open RAN ecosystem.

In this article, we’ll look at a new approach that has recently come to market to address this issue. The emergence of lab-as-a-service (LaaS) has the potential to democratize testing for emerging Open RAN technology vendors.

Open RAN for businesses and technologies

Open RAN disaggregates the traditional radio access network infrastructure (Figure 1). The O-RU handles the RF and digital front end, as well as sections of the physical layer and the digital beamforming functionality. Several O-RUs can be connected to a closely situated O-DU, which runs the radio link, as well as the MAC layer and remaining elements of the PHY. From here, the O-CU takes over, connecting multiple O-DUs to the core network and dealing with radio resource control and data-packet handling, including compression and security.

In addition, a RAN intelligent controller, a software-defined function residing in the cloud to provide programmability, is needed.

Figure 1: Open RAN divides the radio-access infrastructure into multiple standardized modules and interfaces. (Source: Viavi Solutions Inc.)

The network architecture’s specifications are set by the O-RAN Alliance, with each of the above steps standardized. By separating these elements and standardizing their interfaces, Open RAN lets vendors focus on a core set of expertise and capabilities to enable operators to develop the best possible network for their needs.

Beyond 5G, this architecture is poised to play a key role in the development and rollout of 5G-Advanced and future 6G services. As such, the underpinning principles are supported by governments around the world. International cooperation is in place, backed by domestic commitments, such as the U.S. National Telecommunications and Information Administration’s (NTIA’s) Public Wireless Supply Chain Innovation Fund, which has been specifically created to advance the deployment of Open RAN infrastructure.

Certification and badging

Operators need to know that when they add a new component, it will behave as promised and not break other aspects of the networks or introduce a security vulnerability.

Open RAN’s primary advantage is its modular architecture. Rigorous testing ensures products can provide the expected features and performance and can interoperate without issues. Testing a module against the published standards and with a range of vendors’ equipment is therefore critical.

Certification and badging for compliant modules is overseen by the O-RAN Alliance, with evaluation taking place at approved Open Testing and Integration Centers (OTICs). Certificates demonstrate compliance with O-RAN specifications, with badging confirming the equipment’s interoperability or (for complete O-RAN solutions) end-to-end functionality.

Product lifecycle testing

As part of the engineering process, companies need to test their products at various stages throughout development (Figure 2). This allows issues to be highlighted and enables experimentation, adding new features and optimizations in a controlled sandbox environment.

Figure 2: Equipment test requirements extend throughout the product lifecycle. (Source: Viavi Solutions Inc.)

This informal testing process can also help avoid unexpected failures when it comes to the official OTIC certification and badging tests and the costs/delays that these incur.

After OTIC certification and badging are undertaken, further testing is often required for vendors needing to demonstrate the performance of approved, commercial-grade equipment in tests that simulate the actual operational environment in which they’ll be used. These pre-deployment tests identify vulnerabilities, ensure compliance with security standards, and implement necessary safeguards to protect the network and user data.

As we touched on in the introduction, the testing associated with Open RAN development, system verification, security, certification, and pre-deployment is complex, and the necessary equipment and systems represent a significant investment. As such, smaller companies rarely have the resources to establish a dedicated testing lab, adding a considerable competitive barrier as they seek to bring conformant products to market.

Test access difficulties

While it is possible to use an OTIC or commercial test lab services for system verification and pre-certification testing, the number (and geographic spread) of these is very limited, with varying levels of test coverage available depending on location.

One potential solution is to make use of O-RAN Alliance PlugFest events, which are held periodically at OTICs and other vendor-neutral labs. Another is to use initiatives such as the Telecom Infra Project’s (TIP) Test & Integration Group. However, they don’t enable routine testing for development purposes.

As a result, smaller companies have tended to suffer from a two-tier testing service, especially as ongoing testing at an external lab is rarely viable during the product development phase. Moreover, realistic and commercial-grade performance testing for pre-deployment verification is almost never available.

To address this challenge, a hybrid physical and cloud-based model has been developed. This LaaS offering enables preliminary cloud-based testing environments through to extensive multi-cell load and stress testing, which would have previously been inaccessible to smaller vendors. These facilities are still in their infancy, with the first offering having launched just a year ago, but broader industry adoption is happening.

Hybrid, automated LaaS

The LaaS model uses extensive automation to ensure affordability and accessibility, with an on-demand test lab for product development. The hybrid testing model implements a cloud-based lab portal that can be accessed from anywhere in the world, as well as access to a physical lab for pre-deployment, commercial-grade performance testing.

Figure 3: Anechoic testing chamber at the Viavi VALOR lab in Chandler, Arizona (Source: Viavi Solutions Inc.)

Viavi’s lab, Viavi Automated Lab-as-a-Service for Open RAN (VALOR), is the first to receive authorization for Open RAN testing from the TIP in July 2024. Located in Chandler, Arizona, the lab is funded by NTIA’s Public Wireless Supply Chain Innovation Fund.

This LaaS implements a physical lab and cloud-based infrastructure for scalable carrier-grade testing, as well as an on-demand test suite that encompasses the entire product lifecycle. Conformance and performance testing are provided across all classes of Open RAN devices, with end-to-end and interoperability testing with both emulated and real equipment for large numbers of emulated user equipment, channel conditions, and traffic patterns.

VALOR has an anechoic chamber for testing massive MIMO and beamforming over-the-air performance. It also supports security testing, including vulnerability testing that emulates denial-of-service attacks, fuzzing, open fronthaul interface security testing, port scanning, and O-CLOUD security.

While complexity currently presents a barrier to market disruptors, a new approach is emerging to democratize Open RAN testing. With LaaS, smaller companies can now access on-demand, affordable testing facilities throughout the product lifecycle. This hybrid model, combining cloud-based and physical labs, removes a key obstacle to innovation. By enabling comprehensive testing and validation, LaaS is helping to level the playing field, ensuring that the promise of a truly open and competitive Open RAN ecosystem can be fully realized.

The growth and geographic spread of lab services is vital for smaller players to be able to compete in the Open RAN ecosystem. This will enable them to access not only cloud-based labs from anywhere in the world but also local physical labs.

For example, a satellite VALOR Lab has been recently launched at the University of the Philippines in collaboration with the UP Diliman Electrical and Electronics Engineering Institute and the Asia Open RAN Academy. Funded by the U.S. government, the lab aims to further the adoption of Open RAN, lower barriers to entry for new players, and train a highly skilled workforce that can fuel the Open RAN industry in Asia. The lab will be a center of collaboration for mobile network operators, information and communication technology vendors, industry organizations, government agencies, educational institutions, and other development partners.

The growth in the number of LaaS facilities will not only give access to a core set of offerings but also see the development of new innovative and specialist services—in a way, mirroring the Open RAN services they’re testing.

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