Small cells are low-powered radio access nodes (under 6W, as defined by ETSI) integrated into mobile telecommunications networks. Their range is much shorter than that of conventional antennas, ranging from tens to hundreds of metres.
Small cells are deployed as an adjunct to 2G, 3G and 4G macro networks, which remain essential to providing coverage and capacity across an entire territory. Small cell deployment in urban areas will be one of the major issues of 5G. The use – new to mobile networks – of high bands with consequently shorter ranges could bring about a revolution in mobile network architecture. Homogeneous networks made up of conventional relays could thus be supplemented by a potentially large number of small cells, typically to increase local capacity or to cover a limited area.
Incorporating small cells in urban environments will be crucial to the deployment of 5th generation mobile networks. The idea is that they will be deployed on street furniture or building facades. Because of the higher frequencies used by 5G and the trend towards low-energy buildings whose walls attenuate radio signals, there will be a greater need for more low-power relays inside buildings. Small cell deployment in the future could be undertaken by significantly more economic stakeholders than at present: from stadium or building managers to communities, school administrations or shopping centre managers. There will be several challenges to be met, whether in terms of spectrum management, public exposure to electromagnetic fields, competition, access or coordination between the interested parties.
The first challenge will arise from the volume of small cells deployed, which could, in some locations, be up to ten times higher than for conventional relays. This development could lead to a review of the conditions for registering and authorising these deployments, in view of the economic implications for the mobile operators submitting the requests and the administration’s capacity to process them. At European level, in its proposal for a European Electronic Communications Code, the European Commission called for a simplified regime for these small cells, a formal definition of which will be established by a Commission implementing decision.
A second challenge will be the exposure generated by these devices and their acceptability to the general public. The deployment of small cells will change the radio landscape: less radiated power, but more emission points and the use of new spectrum. This could have implications for the exposure measurement and information procedures managed by ANFR. Changes might also be necessary to health and safety provisions, which are outside the Agency’s remit. Further studies and an effective communication policy to inform the public will be essential.
A third challenge will be access (to sites, inside buildings, even to an existing antenna) for stakeholders wishing to deploy or use small cells. Access could be subject to commercial agreements, including small cells as a service (on the same basis as Software as a Service/SaaS), between the mobile network operator and the owner of the small cells, or between the owner of the street furniture or the building in which they are located. This is primarily a regulation issue, but it might have an impact on the databases maintained by ANFR.
ANFR will promote the organisation of small cell deployment trials, monitor progress and publish the resulting reports.
ANFR proposes that a working group meet to examine, for example:
- new stakeholders with a potential interest in installing small cells;
- the conditions governing their installation, including authorisation procedures allowing for the processing of significantly higher volumes, for both mobile operators and ANFR;
- the implications in terms of public exposure to EMF and hence for ANFR, which is responsible for exposure measurement and information procedures;
- where appropriate, the health implications, which do not fall within the Agency’s remit;
- possible conditions for sharing between mobile operators and other stakeholders, given that the potential locations for small cells in densely populated urban areas are necessarily limited.