Open RAN’s role in 6G – A flexible, AI-driven future for telecom equipment

Open RAN (Radio Access Network) created a lot of buzz in the telecom market when the first system was installed in 2020 in Japan. It was expected to quickly replace the proprietary equipment, which often becomes a challenge for telecom service providers (TSPs), in ever-expanding geographies, in particular. However, despite a passage of four years, it has not gained traction the way it was anticipated back them. The objective of this write-up is to understand the nuances of Open RAN in more details, and analyze the reason for this phenomenon.

TSPs face a lot of challenges in upgrading the existing networks under constantly evolving technology, particularly in fast expanding markets like India. In early 2000s, when the Indian cellular telecom market was in its infancy, some of the private TSPs switched over to a model called managed service model, wherein the task of installation of the equipment and its expansion was left to the equipment vendor, depending upon the increase in demand. There was a revenue-sharing arrangement. Around that time, the challenge we used to face at BSNL, being a Government of India enterprise, was going for a tendering process, every time expansion of the network was needed. Now, the equipment starting with 2G radio network was proprietary. So, the only way out was swapping and redeployment of the base stations. A lot of equipment would not work after redeployment, besides the disruptions in the network functioning. At one point, a lot of outdated Nortel make equipment was deployed in BSNL network. With the vendor shutting down shop in less than three years of those deployments, a lot of equipment became a liability for BSNL, and was one of the reasons for it moving into red as a TSP, despite an unfettered mobility boom in the country. One was left wondering as to why we cannot have standard equipment with open standard and interfaces. But, that was not to be!

So, after two decades, when there was a talk of Open RAN (or O-RAN), there was hope that getting over that old handicap was possible. The world’s first commercial O-RAN deployment took place in Japan in 2020 by Rakuten Mobile, a Japanese telecom operator, launching the first fully virtualized, cloud-native 4G and 5G network using O-RAN architecture, with focus on cost-efficiency, flexibility, and innovation. This marked a significant milestone as Rakuten’s network relied on disaggregated hardware and software, enabling the use of multi-vendor solutions. This deployment set the stage for more telecom operators around the world to consider O-RAN for their networks, especially for 5G expansion. A lot of hope was generated. There were expectations that these interconnectivity issues would be things of the past. Somehow, that has not happened yet. So, it made me reflect on the reasons for the same.

How is O-RAN architecture different from the traditional architecture?
Before we analyze the reasons for O-RAN not catching like wildfire, let us try to see where it is different.

The various components of the O-RAN architecture are:

• Radio unit (RU), which is responsible for transmitting and receiving radio signals from user devices, and converting them to digital signals.
• Distributed unit (DU) handles real-time functions like baseband processing, scheduling, and radio resource management. It connects to the RU via an open fronthaul interface.
• Centralized unit (CU) manages non-real-time operations, such as network control, mobility, and routing. It connects to the DU and interfaces with the core network.
• Open fronthaul interface facilitates communication between the RU and DU, making the system modular and allowing for different vendors.
• Core network connects to the CU, handling broader network functions and connecting users to internet and telecom services.
• Cloud/Virtualization represents cloud-native functions, where components like the CU and DU can be virtualized and run on general-purpose servers.

While the traditional architecture too has RU, which is similar to the one in O-RAN architecture, the other component is base band unit (BBU), which has three layers of processing at physical layer, data link layer, and network layer. However, the interface between the two is proprietary.

Advantages of O-RAN over the traditional RAN

• Vendor flexibility. While the traditional RAN is tied to a single vendor, limiting innovation and flexibility, in the case of Open RAN, TSPs can choose different vendors for the radio, distributed, and centralized units. This breaks the vendor lock-in inherent in traditional RAN, where the entire system had to come from a single vendor.
• Cost efficiency. Proprietary hardware is generally expensive, and involves higher long-term costs for upgrades and maintenance, while in case of O-RAN, by using commercial off-the-shelf (COTS) hardware and virtualization, operators can reduce both CapEx and OpEx. Virtualization allows the use of cloud infrastructure for network functions, potentially lowering costs.
• Innovation and faster deployment. In case of traditional RAN, innovation and deployment cycles depend on a single vendor, which may slow down new feature rollouts or adoption of new technologies. O-RAN on the other hand promotes multi-vendor innovation, where new companies can contribute specialized solutions for different parts of the network, driving faster innovation and improvements.
• Network customization and flexibility. In case of traditional RAN, the tightly coupled architecture limits flexibility, making it harder to tailor or scale specific network elements, while in case of O-RAN, the separation of components allows operators to customize and optimize specific parts of the network, such as scaling the DU and CU separately, based on network demand or traffic patterns.
• Cloud-native and virtualization. Traditional RAN relies on physical hardware and lacks the flexibility and scalability that cloud-native functions provide. With the DU and CU able to be virtualized, O-RAN can leverage cloud-native technologies for network management, orchestration, and automation, making it future-proof for technologies like 5G and 6G and also ensure scalability.
• Energy efficiency. O-RAN, by using dynamic resource allocation and optimization techniques (especially with AI/ ML), can achieve better energy efficiency by adjusting the network resources, based on real-time demand.

Thus we can see that practically on most of the parameters, O-RAN scores over the traditional RAN.

Challenges with Open RAN
It is logical to ask as to why is not O-RAN gaining enough steam despite so many advantages compared to the traditional RAN? There are teething troubles at present, which are in the process of getting resolved:

• Performance and integration issues. Open RAN’s multi-vendor approach introduces integration complexities, as different components from multiple vendors must work together seamlessly. Proprietary solutions, on the other hand, offer end-to-end systems that are designed to work together out of the box, ensuring higher performance and fewer compatibility issues.
  For high-traffic, mission-critical applications (such as in urban areas), proprietary equipment often delivers superior latency performance compared to O-RAN equipment currently deployed.
• Lack of mature standards. One of the biggest challenges with O-RAN is ensuring true interoperability between equipment from different vendors. While the O-RAN Alliance is working to establish standards, many operators face difficulties in ensuring that equipment from different vendors can communicate effectively without performance degradation.
• Scalability issues. O-RAN is still in its infancy when it comes to large-scale deployments. The scalability of O-RAN has been tested primarily in smaller, less complex environments (like rural areas or small cells), but it has yet to prove itself in high-demand, dense urban environments, or macro layers. This is where the traditional RAN systems, which are already optimized for these large-scale, high-traffic networks score a point.
• Network reliability. With proprietary equipment, telecom operators benefit from years of refinement and reliability testing. In contrast, O-RAN systems, especially when combining hardware and software from multiple vendors, are seen as less robust in terms of reliability, especially in critical areas like network uptime and performance consistency.
• Security Concerns: O-RAN’s reliance on multi-vendor components and open interfaces increases the potential attack surface for cyber threats. Each additional vendor introduces a new layer of security complexity, which can be harder to manage and secure than proprietary solutions. Traditional RAN systems, built and maintained by a single vendor, often include proprietary security measures that are deeply integrated into the network’s architecture. This reduces vulnerabilities compared to the more open and modular structure of O-RAN.
• Operational and Maintenance Complexity: O-RAN deployments require significant expertise in integrating and maintaining multi-vendor systems, which can increase operational complexity. Managing and troubleshooting a network made up of components from multiple vendors can be time-consuming and costly. With proprietary equipment, telecom operators benefit from a single point of contact for support and maintenance, simplifying network management and reducing operational costs.
• Lack of Commercial Readiness: While O-RAN holds promise, the ecosystem is still relatively immature compared to traditional RAN systems, which have been refined over many years. Many telecom operators find that O-RAN solutions are not yet commercially scalable to meet the demands of large-scale networks.

Then what does the future hold for O-RAN?
Despite the challenges listed above, the future of O-RAN still looks promising. However, its growth will be evolutionary rather than revolutionary, as expected earlier. While it is indeed currently gaining momentum, particularly in rural areas and small-scale deployments, its widespread adoption for large-scale and urban deployments will depend on its ability to overcome several hurdles. Here’s what the future might hold for 5G and 6G:

• Gradual Adoption and Commercial Maturity: Currently, O-RAN is being deployed mostly in niche use cases, such as rural networks, private 5G, and small cells. These limited-use scenarios allow operators to experiment with the technology without risking performance in high-traffic, mission-critical environments. However, there is likely to be a slow but steady Growth. O-RAN could account for up to 25% of the global RAN market by 2028.
• Technological Advancements and Ecosystem Development. O-RAN’s ability to integrate advanced AI and automation technologies will play a crucial role in its future. As telecom networks become more complex with the evolution of 5G and 6G, the need for dynamic, AI- driven network management will grow. O-RAN’s modular structure will make it easier to deploy AI-driven optimization solutions that adjust the network in real time. Stronger Vendor Ecosystem is also likely to play a key role in this process. More specialized vendors are expected to enter the market, offering tailored solutions for specific functions. This will drive innovation, lower costs, and create a multi-vendor environment that benefits telecom operators
• Focus on Scalability and Reliability: For O-RAN to be widely adopted in urban and high- demand networks, it will need to demonstrate that it can handle large-scale deployments with high traffic and complexity. Further, standardization efforts by the O-RAN Alliance and other industry bodies will need to continue advancing to ensure full interoperability across different vendors’ equipment.
• Support from Governments and Regulators: O-RAN is increasingly being supported by governments, especially in Western markets, as a way to reduce dependency on large, dominant vendors. They are keen on promoting O-RAN to foster vendor diversity and ensure greater security in telecom networks, since these are linked to national security issues. Some Governments and telecom regulators are providing funding and encouraging public-private partnerships to accelerate R&D in O-RAN domain.
• Energy Efficiency and Sustainability: As energy efficiency is becoming a critical concern in telecom networks, O-RAN is expected to contribute by offering flexible, software-defined solutions that can reduce power consumption.

6G and beyond: All the points highlighted above, finally go in favour of 6G RAN.O-RAN’s long- term future is thus tied to the development of 6G networks. With the evolution of higher- frequency bands, new network architectures, and a greater emphasis on AI-driven automation, O-RAN is likely play a more prominent role in 6G, O-RAN’s modular design can provide greater flexibility in adapting to the diverse requirements and challenges of 6G networks, such as higher data rates, lower latency, and increased density.

O-RAN vendors can also drive the development of new technologies and features specific to 6G, such as advanced antenna systems, AI-powered network management, and novel network slicing techniques. The modular nature of O-RAN can enable operators to scale their networks more efficiently and cost-effectively to meet the growing demands of 6G services. O-RAN can incorporate advanced security measures to protect against cyber threats and ensure the reliability of 6G networks.

Overall, Open RAN has the potential to be a significant driver of innovation and competition in the 6G era. However, the ultimate success of Open RAN will depend on various factors, including the maturity of the technology, the availability of a robust ecosystem, and the support of both operators and governments.

Outlook
In summary, O-RAN’s disaggregation of hardware and software components offers cost savings, flexibility, vendor diversity, and cloud-native capabilities, making it a compelling alternative to traditional RAN. As O-RAN standards mature, we shall see it play a larger role in future network architectures, particularly in advanced 5G and 6G deployments.

Overall, the future of Open RAN looks bright, with the potential to revolutionize the telecom industry and deliver significant benefits to both operators and consumers. It has the potential to be a significant driver of innovation and competition in the 6G era. However, the ultimate success will depend on various factors, including the maturity of the technology and the availability of a robust ecosystem. Its future will also depend on its ability to scale, improve performance, and demonstrate reliability in high-traffic environments. While it is gaining ground in niche and rural deployments, mainstream adoption for large-scale telecom networks will take time and require advances in interoperability, AI-driven automation, and vendor ecosystems. The backing of governments and the potential for use in future 6G networks will further drive its growth, making it a key part of the telecom industry’s evolution in the coming decade.