About small cells

Indoor mobile device users all want to download and upload files, make video calls and more. But modern building techniques block signals – and therefore block outside-in coverage. Even where a macro can reach indoors, relying on the macro degrades the outdoor network.

The answer? Multi-operator base stations or virtualized platforms are among the most exciting developments of recent years. They have enormous potential for cost-effective indoor coverage. Virtualized platforms that can support multi-tenancy will in turn make neutral hosting an appealing way to deliver cost-effective coverage of commercial property.

SCF is driving the continuing development of cost-effective, small cell-supported solutions to these requirements. It is working with the participants – spectrum owners, enterprises, site owners and a growing number of neutral hosts. It is also working to drive open interfaces – fully open, multi-vendor, 5G small cell designs down to chip level – to ensure the economies of scale modern rollouts require.

As well as small cell designs, ongoing work programs from SCF are looking at multi-operator neutral host solutions, private cellular networks, Edge services, and network management developments. The aim is not only to enable cost-effective small cell deployment in enterprises, offices, local government buildings and shopping centres but to add useful new functionality to those small cells.

Many wireless technologies are making this happen. Small cells are among the most important. The work of SCF includes enabling small cell support for venue-based connectivity. This includes assessing and enabling planning tools, interoperability and new spectrum opportunities. It also includes developing open interfaces and bringing small cells together with the exciting growth of private networks and neutral hosting.

Both private networks and neutral hosting are capable of delivering secure, robust and reliable venue communications – and already have done so in some major venues. For example, in November 2018, American Tower partnered with Ruckus to deliver a CBRS private LTE network deployment at International Speedway Corporation’s newly renovated ISM Raceway in Phoenix. The solution delivers expanded connectivity to motorsports enthusiasts in the grandstands, camping grounds and Midway.

Venue and event-led connectivity often deploy small cells based on their reliability, convenience and ease of installation. New business models like neutral hosting will make small cells an even more attractive option, guaranteeing that multi-operator or private communications can be part of the offering. SCF is committed to enabling this future – and working closely with the groups and technologies that will make it happen.

SCF has launched a new program of work focussed on evolving network management and automation for 5G Era networks. However, most industry attention in this area concentrates on the management requirements of MNOs and public networks. SCF is committed to driving opportunities for small cells and private cellular networks. This means developing a better understanding of enterprise requirements for the management of networks that address the needs of specific vertical sectors.

Early versions of such networks already serve local government, smart cities, transportation, ports, oil, gas and mines, factories, stadiums, malls, campus sites, healthcare and rural services.

And this is only the start. Private cellular networks can provide higher-quality and much more secure mobile connectivity than Wi-Fi. They have a more extensive ecosystem of technology suppliers, system integrators and service providers than proprietary solutions. Commercial conditions are ideal for enterprises and government to leverage private networks for their business-critical and mission-critical connectivity needs. Small cells, 5G and new participants – most notably neutral hosts – will drive this trend.

And SCF is helping to enable this scenario. Small cells are ideal for this new paradigm. They come in an increasingly diverse range of form factors that can deal with diverse deployment environments. And multi-operator capabilities, as well as interoperability, open interfaces and plug and play are further enhancing the effectiveness of small cells in private networks.

SCF work programs and membership reflect the importance of private networks in general and neutral-host-led business models in particular. Our work now involves helping enterprise, industry and government understand the potential benefits of private networks. It also involves developing technical capabilities that will enable small cells to accelerate the development of private networks.

And multi-operator capabilities, as well as interoperability and plug and play, often driven by SCF initiatives, are further enhancing the effectiveness of small cells in private networks, giving small cells a major role in one of the newest and most important developments in the recent history of cellular communications.

In April 2020, we published a comprehensive market position paper about private networks. It lays the foundations for a larger program of work in the enterprise-critical area of private networks, where small cells play a central role.

The objective is to help enterprise, industry and government understand the potential benefits of private networks to support their digital connectivity needs, while helping private network service providers better understand the benefits which are most valued by the different types of customer.

Smartphones, tablets and laptops, and the networks that support them, are making mobile broadband a way of life. Most users will soon expect to be able to access data and voice everywhere.

This need is a major driver for urban small cells — and not just on the street. Shopping centres, stadiums, airports, theme parks and railway stations — any source of high demand or less-than-perfect coverage may also require small cells.

Small cells improve capacity, coverage and end user experience. They also allow operators to generate additional revenue from increased use and new services. Better coverage can even bring benefits to a society and to the economy. And densification — led by small cells — will be the largest contributor to these improvements in the longer term.

Deployment complexity, backhaul, business case, management and interoperability have for some years been seen as barriers by operators. SCF is managing the transition to a highly densified environment in many ways, notably by working with members from across the ecosystem to provide common logical interfaces for the main components of 5G small cells. It is also supporting the drive for a regulatory environment that minimizes unnecessary planning restrictions and avoids lengthy and complex planning application procedures for small cells.

Despite such concerns, most operators regard outdoor small cells as an essential part of their toolkit in delivering mobile broadband. Planned or ongoing examples already exist. Many more are on the way.

Virtualized RAN in the small cell environment is deployable today. It can revolutionize the economics of rolling out large numbers of cells in many dense urban or indoor enterprise locations.

But there are still questions that need answering. Do the benefits of virtualization in the RAN apply equally to macro and small cell deployment use cases? Are current small cell architectures suited to virtualization? Are there unique attributes of small cell transport that impact fronthaul considerations –synchronization, latency, sharing? Can virtualization deliver a phased roadmap – one that is aligned with longer-term 5G directions?

Most importantly perhaps, how do we ensure virtualization supports innovation across a multi-vendor ecosystem?

An early SCF virtualization study highlighted the benefits of centralization and virtualization of the small cell RAN. Once large numbers of cells are needed in a relatively small area, there are many benefits to virtualization, which runs most of the functions of the network as software on central controllers which can be shared by multiple cells.

There is an optimum approach: interoperability. The introduction of our nFAPI specifications offer a set of interfaces for supporting virtualized small cells employing a MAC/PHY split.

Our aim was to ensure interoperability for virtual small cell networks, enabling multi-vendor and multi-operator (or neutral host) deployment.

There is a need to lower barriers to multi-operator, multi-vendor deployment. Our nFAPI specifications can help to realise the benefits of dense networks that are interoperable and future-proof, and that can combine physical and virtual elements.

The benefits of virtualization on effective small cell rollout cannot be over-estimated. Our nFAPI specifications – available in open source nFAPI libraries – aim to ensure that those benefits are realized.

Private LTE or 5G networks offer doctors and nurses a resilient, high-quality-of-service private network across a hospital campus for mobile voice, messaging and data services.

And they are secure. Doctors and nurses need instant access to patient records on the latest mobile devices. A private cellular solution ensures the highest levels of mobile encryption and that all information accessed is only ever on the hospital’s own network. The growth of neutral hosting could enable affordable multi-operator services.

Private networks for healthcare need to cover isolated or hard-to-reach indoor areas. Advances in interoperability, open systems and automated network planning, can make small cell technology cost-effective and easy to install.

The benefits of small cells to healthcare will grow – and new applications, like Edge computing, can be enabled to further enhance the efficiency of hospitals, surgeries and clinics.

Recent trends in the RAN architecture developments are driving this evolution. The trend towards disaggregation and split solutions is making the concept of a single small cell less relevant than a network of small cells.

Such disaggregated, split networks consist of several radio units (RUs), one or more distributed units (DUs) and a centralized unit (CU). Together these form a small cell network and provide the necessary coverage and capacity in an enterprise and/or a dense urban area.

Such disaggregated split SCNs also lend themselves naturally to virtualization, especially of the CUs – and potentially the DUs.

That’s why SCF is addressing such SCNs in its work. Our approach is based on a particular disaggregated split architecture, known as the PHY-MAC split architecture. Such architectures are also called Option-6 architecture or 5G-nFAPI architecture.

SCF is developing the necessary open specifications, not only for the data and control interfaces, but also for management solutions. SCF is also studying deployment aspects, including fronthaul transport considerations, precision planning and much more.

The potential result? Quicker, cheaper small cell design, manufacture and rollout for 5G and densified networks.