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SD-RAN and SD-Core: Software-Defined Open RAN and Mobile Core Projects – What’s Next (Part 2)

Dec 15, 2021
Saurav Das and Ajay Thakur
Saurav Das and Ajay Thakur About the author

This is the second part of a two part blog highlighting ONF’s SD-RAN and SD-Core projects.  The first blog centers on background and accomplishments to date; this blog outlines the exciting development innovations envisioned going forward.

Innovation, specification and development in multiple areas are envisioned in the coming year and beyond:

  • Driving Software-Driven Standards for open and programmable RAN in close collaboration with the O-RAN Alliance;
  • Development of a Portability SDK for nRT-RIC in collaboration with O-RAN OSC and the ecosystem;
  • Development of new xApps and Service Models to enable enhanced RAN control;
  • Oversee operation, bring new features, capabilities, enhancements, and further stability to on-going and new SD-RAN trials;
  • Specification and development of APIs for 5G mobile core runtime configuration and control, subscriber policy management and telemetry;
  • Development of neutral host and network sharing capabilities for the software-defined, cloud-enabled and operated private 5G network;
  • Development of SD-Core interfaces to enable eSIM support;
  • Development of SD-Core interfaces to enable Lawful intercept support.

SD-RAN - Looking Forward

Plans are for SD-RAN to continue to deliver on its vision and enable the required mobile network transformation to realize the following:

Driving Software-Driven Standards

The software-driven standards are effectively an “innovate, realize, deploy, iterate and then specify” approach. ONF’s SD-RAN project includes the necessary artifacts for the community, including ONF, to innovate new xApps, rapidly construct new Service Models, or enhance existing ones in support of them, realize them in lab environments, or out in the field, iterate the Service Models based on practical, operational findings, fine-tune and then bring the proven solution to O-RAN Alliance for specification.  

Portability SDK

As more and more aspects of the O-RAN architecture gets deployed around the globe, it is certain that multiple RIC implementations will find their place in the network. Then, from an xApp developer perspective, we need to enable portability of their xApp across all RIC platforms so that they have as wide a market reach as possible. For this purpose, ONF and the O-RAN OSC, the two open-source consortia developing O-RAN architecture artifacts, are committed to working together towards what is now called a “portability SDK” to do just that. 

New xApps and Service Models

RAN management and control has 4 distinct components: i. Collection of RAN telemetry, ii. Regional RAN management and control, iii. Individual E2 node management and control, iv. Per session, per connected device, or per group of sessions/connected devices management and control. So far, xApp development has focused on the first two. xApps that enable the disaggregation of the RRM functionality from the CU-C, so that we can have programmatic control of handover, carrier/link aggregation operations, traffic steering, as well as xApps that programmatically manage and control the DU-side scheduling operation, through QoS management, RAN Slicing, and multiple antennas operation, through MIMO management and control will be developed along with associated new pre-standard Service Models with additional support.

On-going and New Trials

The on-going Deutsche Telekom trial commenced in October 2021. We plan to continuously oversee the operation, bring new features, capabilities, enhancements, and further stability to this operational network.

We expect additional operators to follow Deutsche Telekom with new lab and field trials for the operationalization of disaggregated, open, software-defined 5G RAN.

SD-Core - Looking Forward

Plans are for SD-Core to continue to deliver on its vision and enable the required mobile network transformation, to realize the following:

Open APIs
A software-defined mobile core will enable runtime configuration and control capabilities for service discovery, subscriber management, network slicing management and control, access control, and QoS management and control. A set of open, widely-accepted APIs that enable operators to deploy and operate potentially a multi-vendor mobile core under different SMOs is needed by the ecosystem. ONF is in the process of helping to define these interfaces using a “software-driven standards” approach. 

Neutral Host and Network Sharing Support
Neutral host and network sharing capabilities enable the owner of the “resources” to share them with potential clients.  These resources may be a subset of the following: infrastructure (towers, power equipment, racks, cabling, fiber connectivity, servers, switches, etc.), spectrum, antennas, gNBs, all or parts of the mobile core. From a mobile core perspective, the owner of the network, providing the neutral host service could provide dedicated instances of NSSF, PCF, AMF, SMF and UPF to clients. Then, the following interfaces will need to be developed and integrated to SD-Core: N31 for network slicing control, N24 for policy, N8 for subscriber data, N12 for authentication, N16 for session management and N9 for use plane.

Further, with cloud centric operationalization, it is possible to realize Neutral Host and Network Sharing as a service, specifically, as Network-as-a-Service, where resources are offered/shared elastically and in a scalable manner. The necessary cloud APIs that enable this capability need to be developed.

Integration with eSIM Provisioning Solutions
SIM cards play a fundamental role in mobile networks by providing a secure means for authenticating devices onto networks. Increasingly, SIM cards are migrating from being a removable secure element into an embedded secure element. This move towards eSIMs simplifies the operations for both the operators as well as their clients.  Integration of the mobile core UDM and PCF components with GSMA specifications compliant 3rd party solutions is necessary for seamless and centralized eSIM provisioning.

Integration with Lawful Intercept Platforms
Mobile Network Operators are mandated by law to empower Lawful Intercept (LI) capabilities in their networks. Such support to be added to SD-Core.

Getting Involved

We plan to continue development efforts for software defined mobile RAN and core into 2022 by leveraging the ONF’s unique model of blending engineering resources from ONF along with engineers and other resources from aligned companies in the ONF community. We invite you to get involved in this exciting endeavor; please contact Oguz Sunay (oguz@onfstaging1.opennetworking.org) if you would like to learn more.

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ABOUT THE AUTHOR Saurav Das and Ajay Thakur
Saurav Das and Ajay Thakur