Small cells are small radio cells that are combined into clusters to increase mobile communications capacities and improve radio coverage of geographically small areas. Such a small cell cluster enables a macro cell to operate much more efficiently and with higher data throughput. In addition, the effort required to build multiple small cells is much less than that required to build a macrocell.
Such small radio cells - microcells, picocells or femtocells - exist in all cellular mobile communications technologies. They are used in GSM networks, UMTS and Long Term Evolution( LTE). Even the hotspots of Wireless Fidelity(WiFi), which operate in license-free frequency bands, are small cells. The coverage area of Small Cells ranges from a few meters to as far as one or two kilometers and depends on the buildings surrounding them. They are also used in closed buildings when macro cells do not provide the required radio coverage. For optimal radio coverage, small cells work with distributed antenna systems ( DAS).
Small Cells offer mobile network operators(MNOs) the opportunity to increase traffic in macrocells. Another option is beamforming, which can be used to selectively illuminate poorly lit radio cells.