Wireless service providers hold a unique position in the global economy. In developed countries, almost every citizen interacts with the connectivity they provide. Wireless is the backbone of communication, commerce, public safety and entertainment. It’s embedded into the daily life of almost every individual, and service providers know their networks are tremendously valuable.
But monetizing those networks requires new ways of working. It started with the vision of virtualizing networks end-to-end, which enables mobile networks to scale faster and opens the door for operators to envision new services, including network slicing, private networks and capacity-on-demand. By first defining the mobile core in software and moving core networks to cloud-based architectures, operators have been able to lay the groundwork for network monetization.
To fully realize this vision, operators now need to virtualize the radio access network (RAN). Some have delayed this step because of misconceptions about cost and complexity. They risk trying to maintain legacy network hardware and architectures in a software-driven world. This stance will end up costing operators much more than a timely investment in modernization. The time is now for the cloudification of the RAN.
Start with discrete steps
In traditional network architectures, the management layer, control plane and data plane are housed in firmware, so the first step to RAN modernization is to move these functions to cloud-ready software.
First, operators need to address the management layer, which is used to configure devices. This can be defined in software and separated from the control plane. Once separated, the management layer no longer needs to reside in firmware and can be moved to commercial off-the-shelf hardware (COTS), which can run in a cloud environment.
The control plane, used to route traffic, can also be defined in software, or virtualized, facilitating programmability. The control plane can also be containerized, so that it will not be tied to just one operating system. Once virtualized and containerized, this function can also be moved to COTS.
Next, operators can decouple the data plane from hardware. This allows them to more quickly scale up new services and allocate network resources efficiently.
The baseband can also be defined in software and moved to COTS. Operators gain flexibility by splitting the baseband functionality into Centralized Units (CUs) and Distributed Units (DUs). The CUs connect via backhaul to the 5G core and manage higher level protocols including Radio Resource Control (RRC) from the control plane, and Service Data Adaptation Protocol (SDAP) and Packed Data Convergence Protocol (PDCP) from the data plane. The DUs manages lower-level protocols including the Physical Layer, Radio Link Control (RLC) and Media Access Control (MAC). Multiple DUs can connect to each CU, and the connection between them is typically called the midhaul.
While the CUs and the DUs can be located in the cloud, the Radio Unit (RU) is at the cell site and will be most effective when managed by a Radio Intelligent Controller (RIC). The RIC can be distributed (near real-time) or centralized (non-real-time). In both instances, the RIC makes the RAN programmable and provides a platform for the integration of new applications that leverage the radio access network, giving network operators new opportunities to cut costs.
In a cloud-based RAN, the RIC will function as part of the service management orchestration (SMO) layer, integrating this software with the radio nodes. The RIC can host applications that will monitor, analyze and predict traffic and activity for each node. Operators can then use automation to control power and bandwidth usage at very discrete levels, cutting costs and boosting network performance.
Invest in proven technologies
The Open RAN ecosystem is constantly innovating and evolving, and operators like NTT Docomo and EchoStar’s Dish Wireless are showing the world how effective this technology can be. The vendors who have experience working with these market leaders have proven their solutions and have gone on to demonstrate further capabilities of Open RAN. For example, VMware by Broadcom, NEC and Softbank successfully converged O-RAN architecture and telco cloud this year. Virtualized RAN applications were deployed as O-CU and O-DU using a vRAN platform optimized for VMware’s Telco Cloud.
O-CU and O-DU are open standards for vRAN applications defined by the O-RAN Alliance. The O-RAN Alliance specification calls for a software-defined core network, and a multivendor cloud-based RAN with the baseband defined by Centralized Units and Distributed Units. This specification effort is advanced by the alliance’s semi-annual Global PlugFests. At the most recent PlugFest (Spring 2024), hosts and participants successfully extended the number of multivendor interoperable configurations in different setups and conditions, broadening the offer of O-RAN solutions for operators.
The U.S. government recently reinforced its commitment to Open RAN with a $50 million grant for DISH Wireless from the U.S. Department of Commerce, which the operator is using to establish the Open RAN Center for Integration and Deployment (ORCID). DISH parent EchoStar manages the ORCID consortium, which includes VMware by Broadcom, Fujitsu, Mavenir and other technology partners. With the help of its partners, EchoStar’s DISH validated O-RAN technology at scale across the country, building an Open RAN 5G network that provides connectivity to more than 240 million Americans nationwide.
NTT Docomo serves more than 20 million subscribers with its 5G Open RAN network and has now taken its Open RAN show on the road by offering the model to other network operators worldwide. NTT Docomo’s OREX Open RAN offering includes virtualized radio base stations, service management orchestration software and services including system integration, operations support and maintenance. More than a dozen companies have partnered with NTT Docomo though OREX, including AWS, VMware by Broadcom, Nvidia, Dell and NEC.
All of these efforts are contributing to the standardized, open approaches that will give operators agility, speed to market and the ability to deliver better customer experiences. When choosing partners, operators need to pay careful attention to which vendors are advancing open standards in the lab and in the field, and which are advancing them primarily in the press and at trade shows.
Prepare a new operating model with the right partner
Many of the benefits of replacing purpose-built routers, switches and baseband hardware with cloud-based software are already well understood, but not all of them. Operators who take this step now will be ready as new opportunities emerge to use mobile networks more dynamically and to serve new customer sets. The danger lies in picking a partner who will try to enact this transformation by replacing one set of siloed systems with another. Operators need to instead choose partners with business models that begin and end in the cloud. RAN transformation relies upon a software-defined network that is truly open and flexible, supported by engineers who are ready to think about the network differently.
Telco engineers need to think about their networks as dynamic, programmable assets. Workforce training and cloud migration can happen simultaneously, and real-world experience is often the best teacher of all. This is the moment for cloudification of the RAN. The tools and skillsets operators need are available in the marketplace. But operators need to choose their partners wisely, selecting those that are focused on software evolution and opportunity, rather than those rooted in legacy telco solutions.