In the 5G era, small cells will be deployed in a far wider range of scenarios, and the form factors and architectures will be much more varied than in the past.

The introduction of virtualized, disaggregated networks means that some small cells will consist of two or three elements, while others will still be all-in-one. Some form factors will be classed as ‘mini-macros’, which can be deployed unobtrusively on street furniture but have performance and power levels close to those of larger base stations. Others will be so tiny they can be embedded into pavements or consumer electronics.

It is clear, then, that old definitions are now inadequate, and we have been conscious of the risks of the industry fragmenting between hundreds of different designs that had insufficient common features to achieve any scale.

To ensure that diversity is supported, but with consensus on key requirements and features, we launched an important initiative focused on achieving a consensual view and concise definition of the types of 5G small cells and the key characteristics of the different types of commercially viable 5G small cell RAN products over the next five years.

Now that this important work has been published as SCF238 5G Small cell architecture and product definitions, we believe it will prove valuable to the whole ecosystem – for vendors and components makers, looking to prioritize their development efforts on the areas of highest demand; for operators, to help as they make their architecture choices; and for external stakeholders such as regulators.

This paper is the result of an SCF member study which has been supported by a major survey of operators, other small cell deployers, and supply chain members. This is the first such study of its kind. It provides an informed view of the most important configurations and specifications for companies deploying small cells between now and 2025. Some key conclusions are:

• Split 6 and 7.x are the most popular among those currently planning disaggregated small cell deployments, as well as dual-split architectures including Split 2. Split 8 is also known to be popular in China for indoor enterprise deployments though it was not represented in the survey.
• Remote integrated and RU small cell products are limited by power consumption, environmental conditions, maximum output power and volume. gNodeB and RUs generally are passive-cooled, and powered by Ethernet (PoE), fiber (PoF) or powerline.
• 2 and 4-layer MIMO is most popular in smaller deployments although 8-layer MIMO is required in some larger enterprise campus, urban and private deployments, and potentially longer term.
• FR1 products dominate with FR2 split 7.2 O-RU support are planned for outdoor campus, urban and private networks, and FR2 split 6 S-RU planned for indoor enterprise.

These and additional analysis shaped baseline small cell product configurations which are detailed in the report; this work will prove essential to the development of hardware component design and reference architectures. Our hope is that this work will help drive increased ecosystem diversity and lower-cost small cell solutions as demanded by the industry and, most importantly, its customers.