Small cells are low-powered radio access nodes or base stations operating in licensed or unlicensed spectrum that have a coverage range from a few meters up to a few hundred meters. Small cells are deployed to increase the mobile network capacity and coverage in localised areas. They can be used to provide in-building or outdoor wireless service.
Global5G.org has analysed deployment and regulatory aspects to help the EU and its member states identify the most effective way to lower the costs of deploying small cells and dense cellular networks. Global5G.org has focused on regulatory factors affecting dense deployment of small cells, looked at the stakeholders impacted and analysed various case studies for additional insights on current barriers and on-going efforts to create an environment enabling rapid and sustainable deployment of small cells.
The main findings are presented below.
The regulatory interventions to facilitate dense small cell deployments require definition or classification of base stations that provide a clear distinction of small cells from conventional macrocells. These definitions or classifications should be standardised and recognised not only across diverse stakeholder groups but also in different countries to facilitate harmonisation of deployment rules and regulations, in accordance with the DSM objectives.
Several base station classifications have been proposed by different SDOs. The currently consensus seems to be building around the IEC 62232 Ed.2.0 base station installation classes as the preferred classification method, with noted support from industry bodies, such as, SCF and GSMA. The IEC 62232 Ed.2.0 guidelines, utilise EIRP and antenna installation height as the classification criteria, and provide detailed elaboration on technical rationale and evaluation approaches for RF EMF exposure.
The adoption of 62232 Ed.2.0 guidelines in regulatory frameworks could be considered a significant step in formulating regulation that facilitates dense small cell deployments.
The requirement for increasingly dense and hyper dense small cell networks (with >150 sites/km2) makes the sharing small cell infrastructure even more critical than in macrocellular networks. The overlapping dense small cell deployments by multiple operators and neutral hosts is commercially and environmentally unsustainable. The need to encourage or mandate sharing has been highlighted by policy and regulatory initiatives, including the proposed EECC directive.
Regulations that permit or even oblige spectrum sharing have significant impact on the implementation feasibility of the active sharing of small cells. Currently, diverse ranges of spectrum authorisation and assignments exist in different countries. This fragmentation presents challenges for the widespread adoption of active sharing of small cells operating in licensed bands. The harmonisation of spectrum sharing regulation and rules targeted by the EECC directive and other initiatives would be a useful step in overcoming this barrier. Moreover, recent specified standards for the operation of small cells in unlicensed (license-exempt) bands is yet another development that could remove the spectrum access barrier in small cell sharing.
The requirement for compliance assessment of small cells in terms of RF-EMF exposure limits is a significant barrier for dense small cell deployments, due to the relatively larger number of small cell sites (both outdoor and indoor) that may need to undergo the costly and time-consuming assessment for product installation compliance.
However, there has been increased recommendations for small cells to have simplified assessments that reduce or eliminate the need for product installation compliance for individual small cell installations. The recommendations are increasingly backed by scientific research results, most of which have concluded that the RF-EMF compliance boundaries typically evaluated based on theoretical maximum transmit powers, create overly conservative EMF limits and may unnecessarily constraint the density of small cell deployments. Furthermore, scientific studies supported by measurements in real deployments could further enhance the validity of these claims.
The small cell deployment processes involve several diverse stakeholders, which may result in overly complex and prolonged processes for dense small cell deployments. Several countries have already adopted measures for simplifying planning approval processes for small cells. This includes: the use of generic permits or exemptions based on internationally standardised equipment classes (e.g. IEC 62232 Ed.2.0 installation classes); harmonisation and simplification of the rules and administrative processes for planning permissions across different local authorities; and incentivising small cell deployments through revision or full exemptions (for small cells) of the base station taxes and recurring fees originally devised for macro deployments. Further benefits of the interventions described could be amplified by harmonising some of those procedures across different countries.
The success of Wi-Fi deployments provides an example of what could be achieved through simplifications of approvals, licensing and permits. The fact that Wi-Fi access points and small cells bear many resemblances, such as, their physical and RF characteristics, and deployment scenarios, provides solid argument for adoption of similar simplified rules for small cells (as used for Wi-Fi access points).