O-RAN (Open RAN) is a Telecom industry initiative that aims to revolutionize the current RAN (Radio Access Network) architecture by embracing software-defined architectures and introducing interoperability and openness. In this article, we will briefly introduce O-RAN and highlight its potential to evolve the RAN to the next level.
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O-RAN
The evolution of mobile communication technologies has been a driving force behind transforming conventional radio access networks. An example is the emergence of 5G, which has defined requirements, such as Network Slicing, to enable network operators to create multiple virtual networks on a single physical network infrastructure.
Even though this shift to virtualization marks a substantial advancement over legacy monolithic architectures, which often hindered network adaptability to different workloads and scenarios, it still poses some limitations.
Conventional Radio Access Networks are typically deployed using proprietary hardware and software and managed through proprietary interfaces. However, due to the constraints imposed by these interfaces, this approach can limit the control of Telecommunication Service Providers over the RAN. It also introduces vendor lock-ins, leading to considerable investments for vendor transitions, interoperability, and infrastructure scaling. Additionally, it limits the market to a few vendors who can provide end-to-end solutions for the complex and demanding Radio Access Network landscape
O-RAN revolutionizes this scenario by leveraging software-defined architecture and open interfaces. It replaces the proprietary hardware/software RAN components with decoupled virtualized network functions (VNFs – for example, Virtual Centralized Unit – O-CU, virtual Distributed Unit – O-DU) atop virtualized infrastructure running on commercially available off-the-shelf hardware.
Further, it introduces a standardized architecture and open interfaces, defining communication between each RAN component to support vendors' interoperability. It also introduces RAN Intelligent Controllers (RIC), which can host custom applications to collect and analyze data and interact with the RAN components for management and control.
The following image shows some examples of Radio Access Network architectures that have evolved through the years.
Figure 1 - Legacy RAN vs O-RAN (Source: Analysys Mason)
Note that although we are focusing on O-RAN in this article, other RAN architectures developed over the years have introduced benefits over legacy non-virtualized architecture. For instance, C-RAN (Centralized RAN) centralizes the BBU component and allows it to handle multiple RRH, while vRAN (Virtualized RAN) applies the same idea of decoupled virtualized network functions, but through proprietary hardware, software, and interfaces.
Benefits
By leveraging a standardized software-defined architecture and modular/extendable RICs, O-RAN facilitates the integration of modern technologies such as AI and ML to support RAN optimization. It can be leveraged for network automation, self-healing, predictive maintenance, and intelligent resource allocation among other use cases, improving network reliability and performance while also providing agility to innovate. It also streamlines the operation, facilitates infrastructure and application orchestration, updates, and upgrades, and reducing operation and maintenance costs.
With environmental concerns becoming more critical each day, O-RAN shows the potential to increase RAN energy efficiency through resource sharing and optimization. It also aligns with sustainability goals and fosters responsible business practices, such as in this initiative from Vodafone, Intel, Keysight, Radisys and Wind River.
By providing openness, O-RAN contributes to a more diversified ecosystem of vendors and service providers, leading to specialization, tailored network deployments, and more flexibility. Open interfaces enable interoperability between equipment and software from different vendors, reduces vendor lock-in and fosters a competitive marketplace. This diversification not only stimulates innovation but also mitigates national security concerns associated with relying on a limited number of vendors for critical infrastructure deployments.
Together, these benefits can lead to lower TCO (Total Cost of Ownership) and faster time-to-market of new features and services.
In summary, O-RAN empowers operators to build agile, cost-effective, and innovative radio access networks that are suited to the demands of 5G and beyond.
Challenges
O-RAN is in its initial stages of maturity, with initial commercial deployments emerging in recent years. Given its status as a paradigm shift in the Radio Access Network (RAN), it is primarily being rolled out through smaller-scale deployments, which pose integration challenges with existing networks. This transition also introduces operational and technical complexities, as organizations navigate the shift from single vendor to multi-vendor supply and support models. They often encounter skill gaps and interoperability challenges when managing this new architecture concept. Furthermore, the adoption of O-RAN infrastructure raises concerns about security vulnerabilities, regulatory compliance, and performance requirements--concerns typically addressed by providers in conventional integrated solutions.
Although this looks like a challenging scenario, industry initiatives such as O-RAN Alliance have been working to address these issues, and industry players are already achieving interesting results (Vodafone) with O-RAN deployments around the world.
As of April 2023, the GSMA alliance noted that although only 18 operators have commercially deployed Open RAN, more than 80 operators have exhibited interest or announced plans to deploy O-RAN solutions, including recent movements by many major operators. For instance:
- Verizon deployed over 130,000 new O-RAN capable radios in its network
- AT&T aims to have 70% of its wireless network traffic flowing across open-capable platforms by late 2026
- NTT announced agreements with Nokia and AWS to support their O-RAN strategy in Japan
O-RAN Alliance
O-RAN ALLIANCE is a world-wide community of mobile operators, vendors, and research and academic institutions working together to enable O-RAN deployments.
As of October 2023, O-RAN ALLIANCE has published 101 technical specifications/reports, many of which are Stage-3 mature and could provide implementable guidance for vendors to develop their products.
The O-RAN alliance also supports Test and Integration (T&I) efforts, approving Open Testing and Integration Centers (OTIC) globally. OTICs provide an open, collaborative, vendor-independent environment for T&I activities. OTICs are also used to provide certification and badges to products that align with O-RAN. Additionally, biannual Global Plugfests facilitate collaboration and accelerate ecosystem maturity by enabling software debug, interoperability tests, and performance demonstrations.
Recently, the O-RAN Alliance released a white-paper highlighting the potential of O-RAN for different industries scenarios.
Is O-RAN here to stay?
The evolution towards O-RAN architecture stands as a transformative milestone in the telecommunications industry, promising increased flexibility, cost-efficiency, and innovation.
By decoupling hardware and software components, leveraging AI for optimization, and fostering interoperability among diverse vendors, O-RAN empowers operators to break free from vendor lock-in, drive competition and stimulate innovation, while also optimizing network adaptability, performance, and resilience.
In this scenario, embracing O-RAN is not just a technological advancement, but a strategic move as operators face pressure from the rise of OTT (Over-the-Top) services and expensive infrastructure deployments for new technologies such as 5G. Moreover, the substantial investments made by major industry players in the technology, coupled with the engagement seen in industry initiatives like the O-RAN Alliance, strongly indicate that O-RAN is here to stay.
Acknowledgements
This piece was written by Guilherme Carrenho, Innovation Expert at Encora. Thanks to Mario Zimmer, Douglas Pereira, Guilherme Leite, Vitor Carreiro and João Caleffi for reviews and insights.
