O-RAN CU Slicing for Providing Vertical's Dedicated RAN Control

Mission-critical applications such as Cellular Vehicle-to-Everything (C-V2X) require fine-grained base station control capabilities. This control must extend across the entire country for nationwide mobility use cases like connected vehicles and logistics. However, the 3GPP RAN architecture specifies a single Central Unit - Control Plane (CU-CP) per base station, preventing Mobile Network Operators (MNOs) from offering RAN control interfaces to industry-specific service providers (called as verticals) without compromising their network control. Consequently, these industry-specific entities leveraging 5G-based services are forced to build costly private networks impractical for nationwide coverage. Enabling diverse applications to exercise base station control necessitates a cost-effective and highly scalable architecture that simultaneously accommodates multiple service providers. This paper proposes “O-RAN CU Slicing,” enabling multiple verticals to control base stations by logically partitioning the CU-CP. The approach creates dedicated virtual CU-CPs (vCU-CPs) for each vertical while utilizing existing RAN infrastructure, avoiding the costs of full base station virtualization. The method implements isolation mechanisms at the Distribution Unit (DU) for Radio Resource Control (RRC) messages, the standardized protocol for base station control. The DU routes these control signals to appropriate vCU-CPs according to user identity parameters. A prototype implementation using OpenAirInterface5g demonstrates processing latencies below 100 milliseconds when handling 100 verticals. These results confirm that O-RAN CU Slicing provides a scalable architecture enabling multiple verticals to simultaneously control base stations across nationwide networks while maintaining operational efficiency.