The TM500 O-RU Emulator testing the O-DU connected over O-RAN open fronthaul.
Backed by the O-RAN Alliance, VIAVI helps customers confidently navigate the complexities of 5G networks by managing interoperability and resolving problems across multiple vendors starting on day one. Successful testing and an open-ecosystem approach is essential to scaling and sustaining 5G.
The O-RAN Alliance, O-RAN Architecture, 5G, and Testing Solutions
What is O-RAN?
An Open Radio Access Network (O-RAN) is a concept based on interoperability and standardization of RAN elements including a unified interconnection standard for white-box hardware and open source software elements from different vendors. O-RAN architecture integrates a modular base station software stack on off-the-shelf hardware which allows baseband and radio unit components from discrete suppliers to operate seamlessly together.
O-RAN underscores streamlined 5G RAN performance objectives through the common attributes of efficiency, intelligence and versatility. Open RAN deployed at the network edge will benefit 5G applications such as autonomous vehicles and the IoT, support network slicing use cases effectively, and enable secure and efficient over-the-air firmware upgrades.
Keep scrolling to learn more about Open RAN, the O-RAN Alliance and the role VIAVI plays.
TM500 O-RAN Fronthaul Demonstration
...Industry’s First Test Suite for O-RAN Specifications
Solutions for 5G Networks
If you’re looking to take the lead in the 5G development and deployment race, you need a partner with the right experience and expertise to help you move forward.
- The O-RAN Alliance
The Open Radio Access Network Alliance was established in 2018 by a global consortium of network operators with the stated goal of evolving radio access networks around the world. This can be accomplished through a transition to virtualized network elements, white-box hardware and open interfaces to the RAN.
Built on the complementary pillars of openness and intelligence, the O-RAN Alliance has established eight discrete working groups with ambitious technical objectives including open fronthaul architecture, RAN cloudification and software specifications for the new radio (NR) protocol stack.
As a key contributor to the O-RAN Alliance, VIAVI collaborates on essential multi-vendor interoperability testing (MV-IOT) to ensure confidence in disparate Open RAN fronthaul components, disaggregated software and hardware elements from multiple suppliers operating in concert.
VIAVI is actively engaged in O-Ran Alliance working and focus groups contributing to interoperability test specifications, E2E test framework, Open fronthaul, xHaul Transport, Plugfest, and Test & Integration Focus Group (TIFG).
- O-RAN Architecture
The reference O-RAN architecture introduced by the Open Radio Access Network Alliance was envisioned with an eye towards next-gen RAN infrastructure with virtualized RAN on open hardware and artificial intelligence intrinsic to radio control.
Functional modules of O-RAN architecture include the RIC non-Real-Time layer to perform operations including policy management and analytics, and the RIC near Real-Time layer to perform time sensitive functions such as load balancing, handover and interference detection. Layer integration allows the RIC near Real-Time layer to benefit from intelligently trained models and real time control functions distributed by the RIC non-Real-Time layer.
The multi-RAT CU protocol stack, deployed on a virtualization platform, supports protocol processing for 4G or 5G while establishing security isolation and virtual resource allocation, among other functions. The open radio unit (O-RU) and open distributed unit (O-DU) elements are integrated through an O RAN fronthaul interface with a well defined lower level split (LLS) that supports eCPRI and RoE. Further definition and standardization of these interfaces will drive interoperability, competition and innovation into the O-RAN supply chain.
Disaggregation is essential for 5G deployment and evolution, enabling mobile operators to open the RAN network and leverage multi-vendor solutions. Open RAN provides new avenues for RAN customization and flexibility that are commensurate with the diversity of 5G use cases and requirements.
By lowering the barrier to entry for new participants into the ORAN 5G ecosystem, the innovation needed to meet ever evolving customer expectations can be fully unlocked. Operators will be empowered to utilize best-of-breed components based on their individual network use case profile. This opens opportunities to reduce development cycles by developing different parts of the network separately while harnessing more innovation horsepower collectively.
- O-RAN Benefits
Operational efficiencies have been realized through past RAN innovations such as cloud RAN (cRAN), but previous advancements did not free operators from vendor lock-in. By enabling an open, multi-vendor RAN ecosystem, O-RAN introduces cloud-scale economies and competition to the RAN. Marketplace factors, combined with a more elastic and flexible RAN architecture that is already taking shape through virtualization, can enable much faster time to market (TTM) than was previously possible.
Moving away from the vendor-specific RAN paradigm not only enables more flexibility for operators, it also minimizes the “secret sauce” that leaves them reliant on a single vendor for all aspects of RAN implementation and optimization.
Competition and proliferation resulting from of new entrants can potentially drive down O-RAN equipment costs. The inter-carrier, interoperability aspects of Open RAN can also be used to increase efficiencies for existing LTE networks as they continue to incorporate the virtualization and disaggregation that are prerequisite 5G RAN deployment.
- O-RAN Challenges
Creating seamless interoperability in a multi-vendor, open ecosystem introduces new test, management and integration challenges that require diligence and cooperation to overcome. In the single-vendor model, accountability is a foregone conclusion and problem isolation and troubleshooting are managed through an established command structure.
Dispersion of vendors could potentially lead to finger pointing when root cause identification is inconclusive. These same complications could plague on-time launch schedules and revenue growth by diluting management and orchestration responsibilities across an array of new O-RAN players.
The enticing Open RAN concept of flexible interoperability also brings challenges for test and integration. To fulfill the O-RAN promise of reduced OPEX and total cost of ownership (TCO), operators must take responsibility for multi-vendor, disaggregated elements and make sure they perform together to maintain QoE standards.
Establishing operator-led, collaborative initiatives such as the open test and integration center (OTIC) can help facilitate the standardization of ORAN component, software, test and technology development across the industry to prepare for real-world, large scale Open RAN deployment.
- How VIAVI Enables the O-RAN Ecosystem
By adopting the O-RAN Alliance fronthaul specifications, developing O-RAN compliant RAN and fronthaul test practices and establishing diverse partnerships within industry workgroups, VIAVI has established a multi-faceted commitment to the success of O-RAN development and deployment. Championing interoperability test methodologies that minimize built-in test dependencies is essential for managing the cost of deployed network infrastructure. This includes the development of methods to evaluate Open RAN field performance.
VIAVI has embraced the end-to-end (E2E) challenges of MV-IOT by supporting and collaborating with our partners on the development of O-RAN test tools extending from the lab to the field. This includes component level wrap around testing, vendor pairing evaluations to validate the function, performance, robustness and resilience of specific combinations, and protocol compliance testing for open interfaces. Holistic evaluation of multiple combinations and system level testing are integral to success and conformance to O-RAN specifications.
- O-RAN Solutions from VIAVI
As a preeminent O-RAN test company, VIAVI has spawned the development of an E2E Open RAN portfolio encompassing robust device, antenna and core test solutions than span the entire Open RAN lifecycle. A comprehensive O-RAN test process must meet the challenge of testing each element and combination in every direction.
Validation: The industry-leading TM500 network tester is designed to validate the user experience (UE) by emulating thousands of mobile devices across multiple cells and radio access technologies. The TM500 mitigates the challenges of multi-vendor O-RAN architecture by providing a test platform agnostic to network disaggregation.
The TeraVM is an essential tool for 5G RAN and core network performance testing.
Verification: The T-BERD/MTS-5800 is the industry’s smallest handheld dual-port 100G multi-purpose test instrument. It has found increasing utility in support of emerging technologies like 5G and O-RAN. By performing O-RAN health verification testing, the MTS-5800 can identify high level issues between the O-DU and O-RU. Packet capture and filtering in this interface can enable advanced troubleshooting and analysis using the Wireshark application onboard or externally.
Radio performance testing to validate successful O-RAN 5G deployment includes beamforming performance verification, radio conformance testing, transmit power measurement and DL modulation quality. The CellAdvisor 5G is a comprehensive, portable RAN test solution with a diverse and easily-upgradable feature set tailor made for advanced 5G and O-RAN deployment and certification tasks. 5G route maps are integrated for coverage verification, and test reports are generated with a simple push of a button.
The O-RAN ecosystem is complex, where the functionality of the near-RT RIC is performed by a mix of xApps. These xApps may be from a variety of suppliers, the challenge for operators is that they need assurance across all stages of the product life cycle from sandbox development through to assurance of network operation that can ensure that xApps from disparate sources operate in a coherent and compatible manner when operating either in an independent manner or chained together to produce the required objectives. This includes validation that the heterogeneous xApps in combination are able to implement the policies of the operator across a mix of subscribers consuming the range of services envisaged for the network across multiple network slices and in an appropriate set of mobility profiles. It must also be validated at scale, making it a use case well-suited for VIAVI End-To-End Wireless Network Test.
Visibility: The VIAVI NITRO platform provides the visibility of the network across the breadth of the radio, RAN, transport and core. As a result, with the richest information on network performance, the autonomic network control systems will be most effective where intervention by the operational network management engineers is required, and resolutions can be implemented within the shortest timeframes. These phenomena will vary as the spatial dynamics of demand for services around the network changes. And as the demand for different mixes of services with novel mobility profiles pushing the resource management capability to the limit, new edge failure cases beyond what was tested at the pre-deployment stage can be exposed and manifest as degraded performance. All of this challenges the network monitoring and assurance system to provide a more complete view of the network, with richer analytics to detect problems, isolate the cause and provide the most appropriate mitigation.
- Accelerating O-RAN
The momentum behind O-RAN as a logical counterpart for 5G RAN disaggregation and innovation continues to build. VIAVI is accelerating next-gen O-RAN networks through active participation in cross functional forums across the telecom landscape. The annual Telecom Infra Project (TIP) Summit is just one example of the collaborate forces engendered when service providers, technology developers, system integrators and test solution leaders pool their resources and expertise.
These workshops, summits and conferences provide a crucial discussion forum for other innovations such as virtual RAN (vRAN). The continuous integration/continuous delivery (CI/CD) approach to vRAN deployment has resulted from an international focus by the telecom community on responsible E2E RAN evolution. This essential spirit of cooperation and open communication can enable the challenges of the O-RAN Alliance to be met and the benefits to be fully realized.