The virtualization and disaggregation of networks are transformative concepts in the evolution of
telecommunications technologies, particularly in the context of deploying 5G networks. They transform the ecosystem by providing operators with agility, performance, and independence while reducing their operational costs.
The dynamics of network virtualization extend the software component of networks to all their layers. It shifts the intelligence from the core network to the radio access network (RAN), closer to the users. This makes resource utilization more efficient and facilitates dynamic orchestration of network services. This evolution brings forth two conceptual approaches that transform the ecosystem.
Virtualized RAN: Often Associated with CloudRAN
The virtualization of the RAN allows operators to deploy radio functions, such as the radio network controller (RNC), in the form of virtual network functions (VNFs). These software components are installed at each site to manage and optimize networks in a scalable manner.
This virtualization is frequently used to implement CloudRAN (C-RAN), an architecture where RAN functions are centralized in a few data centers (edge clouds) instead of being hosted at thousands of sites. These functions, such as the gNodeB (5G base station), are then deployed as VNFs on cloud computing infrastructures.
The combined use of vRAN and C-RAN increases capacity and reduces latency. However, it does not free operators from proprietary solutions, as components offered by suppliers remain largely incompatible with each other.
Disaggregated RAN: Empowering openRAN
The disaggregation of the RAN represents a more advanced stage. It separates RAN components into multiple hardware and software blocks with open interfaces between them. It serves as the foundation for deploying 5G, where radio equipment is disaggregated from signal processing units and control software. This significant evolution has led to the innovative concept of OpenRAN— an architecture based on open standards aimed at ensuring connectivity and interoperability between RAN components from different vendors. This approach will provide operators with greater
flexibility, allowing them to choose the standardized block that best suits their specific needs and budget for each component, rather than opting for closed solutions from a limited number of proprietary manufacturers.
Several operators around the world have already deployed
CloudRAN projects
• China Mobile (China) has undertaken large-scale deployments to enhance network performance.
• AT&T (USA) initiated the ‘Network Cloud’ initiative for virtualizing network functions, including RAN.
• SK Telecom (South Korea) has worked on CloudRAN projects to improve the efficiency of its 4G and 5G networks.
• Deutsche Telekom (Germany) has experimented with RAN virtualization and CloudRAN architectures to optimize its networks.
• Verizon (USA) has explored RAN virtualization to enhance the flexibility and scalability of its networks.
The rise of new players and momentum towards standardization
The concept of OpenRAN is reshaping the telecommunications landscape. While traditional equipment providers strive to maintain their current market shares with closed virtualized solutions, new entrants are getting involved in RAN disaggregation.
Startups and software providers are positioning themselves to provide both hardware and software functionalities. Companies like Altiostar, Mavenir, and Parallel Wireless are actively working on OpenRAN solutions.
These actors are actively engaged in standardization efforts initiated by the ecosystem in recent years to regulate RAN disaggregation and the development of open standards.
• Two standardization organizations, IEEE and 3GPP, play a crucial role in establishing standards and technical specifications.
• The O-RAN Alliance, founded in 2018 by five operators, including Orange, brings together around thirty operators, vendors such as Nokia and Ericsson, and software providers. As a proponent of RAN disaggregation and openness, it focuses on developing open specifications and standards.
Transformative Solutions
OpenRAN, with its virtualized, disaggregated, programmable, intelligent, and interoperable functions, will provide operators with measurable benefits in terms of flexibility, agility, scalability, efficiency, and cost reduction.
• An open RAN will enable them to deploy and optimize new services rapidly and at lower costs, thus meeting the evolving requirements of 5G networks.
• Centralizing network equipment will improve maintenance efficiency through simplified management, reduced on-site visits, faster updates, and resource optimization.
• Increased competition among more diverse suppliers will encourage innovation, facilitating the integration of new technologies and equipment.
• Virtualizing the RAN will decrease energy consumption and, conse-quently, the operator’s carbon footprint by shifting some of the network intelligence into the software layer. This will reduce the amount of energy-consuming hardware used and optimize network resources through dynamic allocation based on the actual needs of the network.
Raising caution
In the long term, network softwarization offers considerable advantages in terms of operational efficiency and the ability to meet evolving user needs. Nevertheless, it presents technical and human challenges that must be addressed.
• Security is a major concern. With softwarization, the attack surface of open and shared networks increases, necessitating enhanced security measures.
• Interoperability among different RAN components adds complexity. Efficient orchestration and management of virtualized networks will be essential to ensure smooth operation.
• Operators must ensure that their solutions adhere to standards to guarantee interoperability with other systems.
• Lastly, these developments raise questions regarding skills transformation and change management within companies. It will be necessary to train and adapt teams to fully leverage the benefits offered by network softwarization.
Open RAN and the virtualization of network functions pave the way for network automation using AI and machine learning-based technologies. They serve as catalysts for disruptive innovations for both operators and users.
OpenRAN: A Model Deployment and Trial Initiatives
• Rakuten Mobile (Japan), a pioneer in large-scale commercial OpenRAN, utilized OpenRAN solutions to establish a 4G and 5G network based on open standards.
• In Europe, the adoption of OpenRAN depends on various factors: local regulations, specific network requirements, and commercial opportunities.
• In the UK, Vodafone has committed to adopting OpenRAN to diversify its RAN vendors and optimize costs.
• In Spain, Telefónica has conducted pilot projects and is collaborating with various companies to develop and test OpenRAN solutions.
• In France, Orange has experimented with OpenRAN as part of its Pikeo pilot project and is partnering with others to explore solutions.
Gregory CASAS, Consultant of Project Management & Network Deployment Division at Sofrecom
Olivier MUGNIER, Consulting Director Network Engineering at Sofrecom
Chady ZAKHIA, Head of Project Management & Network Deployment Division at Sofrecom
