What is the use of SMO as defined by Open RAN?

SMO (Service Management and Orchestration) defined by Open RAN Alliance is a wireless resource automation platform for mobile communications.SMO framework specification is defined by Open RAN Alliance as a component of OSS system to support a variety of deployment options to meet the needs of end-users; SMO can be deployed in a distributed system, but also deployed in the telecom cloud services and other places.

I. Platform Architecture The SMO platform is shown in the following figure (1) The architecture includes consists of O-CU (Open Central Unit), O-DU (Open Distributed Unit) and Near RT-RIC (Near Real Time Radio Intelligent Controller), which are defined as cloud-native virtualization functions running on cloud infrastructure, also known as O-Cloud.

Ⅱ. SMO features are responsible for overseeing network functions and O-Cloud lifecycle management.SMOs include Non-Real-Time Radio Intelligent Controllers or Non-RT-RICs.The architecture defines a variety of SMO interfaces, O1, O2, and A1, that allow SMOs to manage multi-vendor Open RAN networks.ORAN is standardizing on extensions to the O1, A1, and R1 interfaces to enable a competitive ecosystem and accelerate new features to market. ORAN is standardizing extensions to the O1, A1 and R1 interfaces to enable a competitive ecosystem and accelerate time-to-market for new features.

• Supports licensing, access control and AI/ML lifecycle management and legacy northbound interfaces;
• Support for existing OSS features such as service orchestration, inventory, topology and policy control;
• The R1 interface allows rApp portability and lifecycle management. By supporting third-party Equipment Management System (EMS) specific proprietary southbound interfaces, SMO will be able to automate existing, purpose-built multi-vendor RAN as well as Open RAN networks.

Ⅲ​. SMO interfaces mainly include:

• R1 interface:R1 interface for multi-vendor rApp, designed to support multi-vendor rApp portability and provide value-added services for rApp developers and solution providers; the interface enables Open APIs to be integrated into SMO; as a service it includes: service registration and discovery services, authentication and authorization services, AI/ML workflow services, and A1, O1 and O2 related services.
• A1 Interface: The interface is used for policy guidance; SMO provides fine-grained policy guidance, such as allowing user devices to change frequencies, as well as providing other data enrichment capabilities to RAN functions through the A1 interface.
• O1 Interface:SMO supports the O1 interface for managing OAM (Operations and Maintenance) for multi-vendor Open RAN functions, including fault, configuration, accounting, performance and security management, software management, and file management functions.
• O2 Interface:The O2 interface in SMO is used to support cloud infrastructure management and deployment operations for Open RAN functions in the O-Cloud infrastructure hosting network.The O2 interface supports the orchestration of O-Cloud infrastructure resource management (e.g., inventory, monitoring, provisioning, software management, and lifecycle management) and the deployment of Open RAN network functions to provide logical services for managing the lifecycle of deployments using cloud resources. M-Plane:SMO supports the organization of Cloud infrastructure resource management (e.g., inventory, monitoring, configuration, software management and
• M-Plane: SMO supports the Open FrontHaul M-plane based on NETCONF/YANG as an alternative to the O1 interface to support multi-vendor O-RU integration. the Open FrontHaul M-plane supports management functions including boot installation, software management, configuration management, performance management, fault management, and file management.

IV.RAN Optimization The SMO framework can be used for RAN optimization with the help of Non-RT RICs and rApps. non-RT RICs enable non-real-time intelligent RAN optimization by providing policy-based guidance using data analytics and AI/ML models. non-RT RICs can take advantage of SMO solutions, such as data collection and configuration services for O-RAN nodes.

Additionally, rApps that are modular applications can leverage the functionality exposed by the non-RT RIC and SMO frameworks through the R1 interface to perform multi-vendor RAN optimization and assurance.