With the increasing pace of 5G rollout, network providers worldwide face growing expectations to deliver massive data volume over different types of spectrum while adhering to varying latency needs. Increasingly, operators and equipment manufacturers alike are adopting open radio access network (RAN) architectures to support successful RAN deployment and management at scale. Advancements in Open RAN networks, such as those made possible by O-RAN ALLIANCE specifications, allow more efficient scalability to meet rising data demands with reduced infrastructure deployment costs.
Even so, a disaggregated O-RAN environment creates complexities that need to be addressed, all too often leaving network operators with the burden of ensuring conformance, interoperability, and performance. To streamline successful implementation of critical O-RAN use cases, VIAVI recently enhanced its Test Suite for O-RAN Specifications, a comprehensive set of testing modules for lab validation, field deployment, and service assurance.
Roadblocks Ahead
When planning deployment and management of networks based on Open RAN architecture, the most pressing concerns for operators center around ensuring interoperability, manageability, optimization and end-to-end performance in a multi-vendor environment. Designing the 5G RAN requires careful consideration of features including multiple-input, multiple-output (MIMO) antennas and multi-band carrier aggregation. This poses a challenge for successful growth and maintenance of the networks, which now need to support multiple technology generations – 3G, 4G and 5G – while scaling to meet rising data demands.
Imagine a network where RAN components such as the central unit (CU), distributed unit (DU) and radio unit (RU) are all provided by multiple vendors. This type of environment makes it even more challenging to identify and isolate issues. With the adoption of Open RAN, operators need to validate everything works together before it goes into the live network. Yet addressing these issues requires more than testing the interoperability of distinct vendor technologies. Operators need to see how the technology interacts with legacy 4G equipment in the network, as well as how it responds to different user equipment (UE) environments.
Troubleshooting issues after the network has been deployed is important as well. In a multi-vendor environment, it is more difficult to identify product-related network performance issues than it was in a single-vendor network. With an Open RAN network, operators need open standards and vendor-agnostic validation and troubleshooting solutions to resolve network performance issues.
Navigate O-RAN Challenges
Successful operation of disaggregated RAN networks will depend on the ability to integrate system components and meet network key performance indicators (KPIs) in a multi-vendor environment. Operators need to have the confidence that all components in the O-RAN network have been validated and verified in a trusted and controlled environment, and all open interfaces and components are working correctly, so that network performance is at least equal to that of a single-vendor network.
Critical aspects to be evaluated include:
- End-to-end network performance
- Handover and mobility scenarios
- Ability of the network to handle large numbers of UEs carrying different types of traffic
- Robustness of the fronthaul O-RU to O-DU connection.
Access to the latest testing tools and resources throughout the lifecycle of an O-RAN network can help operators ensure that network performance issues are identified and resolved quickly to meet their KPI goals. These include:
- Tests for functionality, performance, reliability and resilience
- Subsystem wrap-around tests
- System-level tests
- Protocol compliance for open interfaces and protocols
- Performance monitoring of open interfaces and protocols to ensure optimum operation
As a leading supplier of network test and validation for operators and manufacturers worldwide—including all Tier-1 network equipment manufacturers—VIAVI is active in Open RAN specifications development, including co-chair of multiple working groups at the O-RAN ALLIANCE, and editor of interoperability test specifications in the open fronthaul and open interfaces working groups. These active contributions have enabled VIAVI to develop partnerships with best-of-breed vendors, and to deliver the most comprehensive test platform on the market for O-RAN networks.
Based on best practices from the 2020 O-RAN ALLIANCE plugfest and customer engagements around the world, the enhanced VIAVI Test Suite for O-RAN Specifications includes interoperability use cases of critical importance, such as:
- O-RAN Subsystem and End-to-End Testing
- 4G and 5G Transport Network Testing and Synchronization
- Network Assurance, Troubleshooting and Optimization
Capture the Open Opportunity
O-RAN networks hold tremendous promise for mobile network operators through an open ecosystem that removes vendor lock-in, while creating the foundation for automation and virtualized network elements, enabling increased speed and scalability to capture the fast-growing 5G market. For today’s operators to speed service delivery and reap the benefits of O-RAN architecture, however, interoperability challenges need to be overcome. This will require integration of meticulous test and validation processes from the lab to deployment, and beyond.
Learn more: Click here to experience a virtual best-of-breed ecosystem demo presented by VIAVI and the O-RAN Alliance at MWC Shanghai 2021.