What is a small cell

Small cell definition

A small cell is a radio access point with low radio frequency (RF) power output, footprint and range. It is operator-controlled, and can be deployed indoors or outdoors, and in licensed, shared or unlicensed spectrum.

Small cells complement the macro network to improve coverage, add targeted capacity, and support new services and user experiences. There are various types of small cell, with varying range, power level and form factor, according to use case. The smallest units are for indoor residential use; the largest are urban or rural outdoor picocells.

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  • Today a modern mobile communications network comprises a combination of different cell types and different access technologies.

    These networks are evolving heterogeneous RAN environments – or HetNets ­– that can include conventional macro assets, RAN transport, small cells and Wi-Fi. It is important that such HetNets of differing domains are integrated. This is why SCF puts HetNet densification at the heart of its work, including defining a target architecture for supporting the automation of the HetNet, including integration across the end-to-end domains.

  • Newer small cell designs include clusters of ‘virtualized cells’ run from a central controller; and low power remote radio heads.

    Virtualization of network functions is an industry transition – dedicated ‘boxes’ using bespoke hardware are being replaced with software which can run on standard computing platforms. Virtualization brings important benefits to mobile operators, including scalability, agility, cost reduction and the ability to carve off slices of their network.

    Applying virtualization to the RAN first requires the base station to be ‘functionally split’ into physical and virtual network functions (with an ‘x-haul’ interface in between).

    To avoid industry fragmentation around the increasing adoption of virtualized small cell base stations, SCF developed an open interface called nFAPI to support a strong ecosystem with interchangeability of parts, laying the foundation for multi-vendor and multi-operator virtualized small cell deployments. The resulting ‘networked FAPI’ or nFAPI interface supports a MAC/PHY functional split and enables centralization and virtualization of higher layer base station functions.

  • Small cells will be a crucial component of 5G networks, because they increase network capacity, density and coverage, especially indoors.

     

    From the early stages of 5G planning to the detailed evolution of 5G requirements, it has been clear that small cells are of key component to making the path to 5G practical and profitable. This is because 5G requirements demand:

    And it is clear small cells as the only viable option for several key 5G Era deployment scenarios:

    • >6GHz spectrum, where propagation limits cell sizes
    • Radios using shared and license-exempt spectrum, which generally mandates lower power
    • Areas of hyperdense traffic demand in cities, stadia, transport hubs etc.
    • Scalable, low-cost deployment using a low-skilled, third-party, or end-user workforce
    • Small/medium enterprises requiring self-deployed indoor coverage
    • Coverage extension in rural, remote, moving and temporary deployment scenarios with equipment size, weight or power constraints.

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