O-RAN Redefining the Future of Wireless Connectivity

The 5G Open Radio Access Network (O-RAN), brings a new concept to the wireless industry by introducing openness, interoperability, and disaggregation in network architectures. Because O-RAN decouples hardware from software, it not only makes networks more agile, but it also simplifies their management. Operations are streamlined and the total cost of network ownership is reduced by up to 30 percent. Together, these factors are driving greater support for 5G O-RAN and contributing to the growing industry appetite for network modernization.

Achieving true interoperability, however, is no simple task.

Ultimately, the success of 5G O-RAN deployments hinges on a multi-pronged approach involving a blend of collaboration, standardization, and advanced automated testing tools. By harmonizing testing processes and fostering an open dialog among vendors, individual companies will be better prepared to handle O-RAN deployments, paving the way to a more interconnected and flexible mobile network landscape.

What is O-RAN and How Is It Different from Traditional RAN?

Formalized only a few years ago with the foundation of the O-RAN Alliance, O-RAN’s goal is to enable interoperability among components from different vendors — redefining the future of wireless connectivity.

In cellular wireless infrastructure such as LTE and 5G, the radio access network (RAN) connects base stations to our smartphones and other mobile devices. The traditional approach to the RAN relies on closed, proprietary systems based around one vendor’s hardware. However, the mobile network operators have been looking for a solution that is more flexible, lower cost, and easier to automate.

O-RAN promises to be this solution by introducing open interfaces and standardization, which allows operators to mix and match network components from different vendors. Openness and interoperability break down vendor lock-in, foster innovation, and give operators greater flexibility and control over their networks. Ideally, the O-RAN environment will permit seamless, secure interoperation between any hardware and software within a cellular network, regardless of vendor.

For example, Nokia and Deutsche Telekom recently announced they have begun to deploy a multi-vendor Open RAN network with Fujitsu in Germany. Nokia will deploy its O-RAN solution in Deutsche Telekom’s commercial network, and expects it to match traditional, purpose-built RAN in terms of features, service, and performance.

There are some key benefits to the O-RAN architectural concept, for example, promoting vendor diversity and competition, encouraging innovation, and driving down costs. O-RAN enables operators to select the best-of-breed components from different suppliers, creating a more flexible and scalable infrastructure. Network management and deployment are simplified by standardizing interfaces and promoting automation. O-RAN facilitates the introduction of new services and technologies and can be credited with accelerating the pace of innovation in the wireless industry.

The Basics and Benefits of O-RAN

An O-RAN system disaggregates a RAN into three primary building blocks: radio units (RUs), distributed units (DUs), and centralized units (CUs). The RU is located at the cell site (near or integrated into the antenna) and processes radio frequency signals. RUs convert frequency-domain digital signals from the DU into time-domain analog RF signals for transmission and reception. The RU handles modulation, demodulation, and amplification, tasks that enable direct communication with end-user devices.

The DU and CU work together to send the digitized radio signal into the network. The DU is typically situated close to the RU at the cell site, and acts as a mediator between the RU and the CU. The DU handles computationally intensive tasks like error correction, encoding, and decoding, to ensure data flow is efficient and use of the radio spectrum is optimal.

The CU is usually deployed at a centralized location and oversees the network’s control plane. Its role involves handling functions related to session and mobility management and orchestrating network resources. By managing high-level operations, the CU ensures seamless connectivity and network consistency across multiple DUs and RUs.

The separation of RU and DU processing, paired with CU network control, promotes flexible network deployment and management. This modular approach enables operators to optimize network performance, reduce latency, and efficiently scale resources to meet a range of shifting demands. The resulting network infrastructure is a dynamic and adaptive environment, designed to make 5G networks more flexible, scalable, and efficient.

O-RAN Today: Progress, Hurdles, and Industry Responsibilities

While diversity fosters innovation and competition, factors that drive down costs and improve quality, it also complicates network management and standardization. This is illustrated by the notable misalignment of specifications between two major forces in the O-RAN market: 3GPP, the group behind the 5G standard, and the O-RAN Alliance’s own set of standards. Consensus on a single set of standards is necessary, unlocking development of robust translation layers that can bridge differences, eliminate confusion, and avoid market fragmentation.

New players in the O-RAN ecosystem — particularly in the RU space — add value as well as challenges. However, while an increasingly diverse ecosystem offers network operators a broader range of choices for radio components, it also adds layers of complexity to managing the overall network, with corresponding intricacies in communication and operational efficiency.

These issues beg the question: is the O-RAN ecosystem enriched by diversity or made more cumbersome? The answer is that finding an optimal middle ground is in order. Adopting collective responsibility, the industry must strike a balance between the promise of revolutionizing the telecommunications landscape and managing complexity.

Accelerating Time to Market With O-RAN Radio Testing

The openness of O-RAN has both advantages and drawbacks. Competition and choice are benefits, but with significant concerns over compatibility, management, and security. The situation is complicated further by the proliferation of market players, particularly the growing number of radio architects who may or may not have the depth of expertise required to develop successful O-RAN solutions.

The resulting market is highly fragmented, which raises the possibility of potential conflict between compatibility and interoperability of deployed O-RAN components that may be manufactured by different companies. Although specifications and interfaces defined by the O-RAN Alliance are intended to improve compatibility, inconsistencies can result from varied interpretations of the standard from vendor to vendor. Vendor management is emerging as a critical issue, pointing to challenges in troubleshooting and accountability when multiple vendors contribute to a single system.

Security is an important issue: what is the strategy to ensure system-level security in the disaggregated O-RAN climate if each vendor operates in isolation, focused only on their portion of the system?

Success Requires Effective Testing

Successful O-RAN strategies require early, thorough, and meticulous testing of deployments. Testing is either isolated or handled at the system level. Isolated testing assesses components individually, delivering assurance to designers and system integrators that each system element meets specifications.

Testing itself is challenging, however, especially for new entrants to the market. For isolated testing of RUs, systems require specialized equipment such as a DU emulator, vector signal generator (VSG), and vector signal analyzer (VSA). The resulting testing setup is complex and leads to testing times that can exceed one hour.

System-level end-to-end testing of the entire O-RAN system is generally handled by the system integrator or operator. Most system-level testing focuses on the RF performance of base station elements such as the transmitter and receiver, and includes testing for signal quality, strength, and coverage.

This is another reason vendor management stands out as one of the most important factors in rooting out the causes of potential failures. Communication among vendors, even in a disjointed marketplace, is essential to identifying and resolving issues encountered during testing.

Advanced Testing Solutions

As 5G O-RAN proliferates, individual vendors must reduce overhead and processing time for isolated testing operations, while the broader ecosystem needs more efficient system-level test options.

Advanced testing solutions are helping to further these goals, focusing on validating the performance, functionality, and interoperability of O-RAN Radio Units (ORUs). An example is LitePoint’s IQFR1-RU, the industry’s first fully integrated tester that supports RF parametric measurements as well as the O-RAN fronthaul functionality necessary to configure the interface with the O-RAN RU under test.

The IQFR1-RU eliminates the dependency on external DU emulators and provides fully integrated MIMO signal generation and analysis. Overall, its comprehensive testing and high-level integration create a simplified solution for testing 5G FR1 O-RUs, reducing testing time and accelerating time to market.

Testing Is at the Heart of O-RAN Development

O-RAN is at a pivotal juncture, as the 5G ecosystem works to balance complexity with the promise of revolutionizing the telecom landscape. For seamless integration, vendors must align their interpretations of technical specifications. Ongoing collaboration may also involve the development of new governance structures or third-party bodies to oversee and facilitate this integration. Research and development investments are required to solve technical roadblocks that currently limit interoperability, even as legacy telecom vendors may no longer be the only bedrock research and development players as new companies enter the market. Only by clearly and consistently addressing these issues can O-RAN capitalize on its promise to the telecom world.

It is in this complex landscape that isolated testing and system-level testing create a foundation for addressing compatibility, management, security, and market fragmentation issues in O-RAN deployments. By ensuring that O-RAN components meet strict standards for performance, interoperability, and security, testing plays a vital role in advancing the development of successful, secure, and manageable O-RAN solutions.

This article was written by Middle Wen, Senior Product Manager, LitePoint. For more information, go here .

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