SCF extends pioneering work in SON to support 5G era automation

A heavy dose of automation is a key goal for most operators deploying next generation networks. The more they extend their 4G and 5G networks with dense hotzones of capacity, or deep indoors, the more cells they will roll out. These numbers will become impractical to manage and optimise manually, especially with rising customer demands for high quality connectivity and even critical communications. Supporting many of the services envisaged for 5G, from massive numbers of IoT devices to immersive user experiences, will require near-real time adjustment of the network to ensure the best connection at all times.

Full end-to-end automation remains a relatively distant goal for many MNOs, but there are important steps towards that end point, and Small Cell Forum is engaged in making those steps clear and deployable for operators of all kinds.

One of the first and most important examples of automation being developed for the RAN is SON (self-organizing or self-optimizing network), which has been a central element of SCF’s work programme and outputs for some years. With the opportunity to accelerate at-scale densification at stake, SCF’s latest SON-related release is a foundational paper entitled‘ Small Cell SON and Orchestration from 4g to 5G’.

This paper offers a valuable set of recommendations for how automation should be baked into 5G standards, products and processes. This will provide a clear and essential blueprint for anyone considering next steps in small cell management, and particularly the best roadmap towards full automation, including orchestration of virtualized networks and of a wide range of physical and virtual elements.

The paper also considers how technology changes such as virtualization, slicing, machine learning and artificial intelligence, and RIC (RAN intelligent controller) will impact on SON and orchestration in future.

Though future-looking, the paper also brings together, and builds on, a wealth of existing knowledge gained from years of defining SON standards and interfaces. The small cell industry has – by necessity – had to build in robust automation to enable user-deployable plug-and-play small cells at large scale. For instance, it has defined SON APIs (application programming interfaces) which enable multivendor networks of SON-capable cells, and has conducted plugfests to improve the level of SON feature interoperability between equipment from different vendors.

This work will provide an important foundation for the technologies which will enable a new level of scale and sophistication in 5G era small cell networks and the way they are managed and automated. In addition to far larger numbers of cells, there will be many other elements to manage including edge computing nodes, backhaul links, firewalls and IoT sensor gateways.

Small cells have been a proving ground for SON, but it will become more mission-critical in the 5G era, as well as being enhanced in terms of its capabilities, for instance by extending to the end-to-end network, and by introducing AI/ML analytics. For this reason, SCF is building on its existing work in standardizing SON features.

The migration to 5G architectures, including virtualized and disaggregated networks, will be a key driver for automation. In a survey of 68 MNOs conducted by SCF in Q4 2019 (see Figure 1), respondents identified their key requirements for next generation SON. This shows that open, multivendor SON with the resulting flexibility and cost-effectiveness lead the way in terms of next generation requirements. SCF work items and plugfests directly support these goals.

Figure 1. Requirements for next generation SON (68 MNOs provided a free list of all their desired capabilities. From a list of the eight capabilities that were most commonly cited, they then selected their top three).

Adoption of these new technologies could greatly increase the number of network processes that are automated, and that in turn will drive the scale of small cell deployment by making it simpler and more affordable.

The number of use cases will also greatly expand in the 5G era. For instance, the use of very disparate frequency bands, each with their unique propagation characteristics, will require a diverse set of tools for  capacity and coverage planning.

Amid all this network and service evolution, it is more vital than ever that the industry supports open interfaces in SON and orchestration, and this remains the central goal of SCF’s work in these areas. Its interfaces will allow operators the flexibility to adopt solutions from different vendors, while evolving towards future approaches such as the RIC (RAN intelligent controller).

The key takeaway from the new paper is that setting open standards now will give operators confidence to lay the foundations for automation, and to cope better with the inevitable and rapid changes that will come with 5G. In order to manage hyperdense and heterogeneous small cell networks, SCF believes that traditional SON will need to be enhanced with advanced algorithms which make it more dynamic and which extend its reach beyond the access network to cover core, backhaul and IT assets. It will eventually leverage AI/ML techniques to evolve beyond just automating the optimization of the network, and to add a hefty dose of intelligence to those automated decisions.

In this context, a gradual movement from native SON and radio resource management (RRM) to a RIC architecture is likely. The transition will be filled with challenges and the industry needs to come together to smooth this transition if the RIC architecture is to succeed. In the 5G era, not only will multivendor interoperability between any of the elements be crucial, so will multi-radio networks (cellular, Wi-Fi and shared spectrum). Furthermore, as the networks become virtualized, orchestration by a single framework that also includes business level policies will be critical.

The new paper is just the start of a series of work items focused on management, automation and orchestration of next generation networks, including valuable collaborations with complementary efforts like ONAP (Open Network Automation Protocol), which is more focused on macrocells. With these papers, specifications and cooperations, SCF is confident that it will lay strong foundations for intelligent automation of the next wave of dense small cell networks.