Small cells are low-powered cellular radio access nodes that operate in licensed and unlicensed spectrum that have a range of 10 meters to a few kilometers. They are "small" compared to a mobile macrocell, partly because they have a shorter range and partly because they typically handle fewer concurrent calls or sessions.

 

They make best use of available spectrum by re-using the same frequencies many times within a geographical area. Fewer new macrocell sites are being built, with larger numbers of small cells recognised as an important method of increasing cellular network capacity, quality and resilience with a growing focus using LTE Advanced.

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Small cells may encompass femtocells, picocells, and microcells. Small-cell networks can also be realized by means of distributed radio technology using centralized baseband units and remote radio heads. 

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Beamforming technology (focusing a radio signal on a very specific area) can further enhance or focus small cell coverage. These approaches to small cells all feature central management by mobile network operators. 

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Small cells are available for a wide range of air interfaces including GSM, CDMA2000, TD-SCDMA, W-CDMA, LTE and WiMax. Wi-Fi is a small cell but does not operate in licensed spectrum and therefore cannot be managed as effectively as small cells utilising licensed spectrum. Small cell deployments vary according to the use case and radio technology employed.