A femtocell is a small, fully featured, low-powered cellular base station. A femtocell is typically connected to a mobile operator’s network via a standard broadband DSL or cable service. Femtocells are so small they resemble Wi-Fi modems. They are designed for homes or business establishments.
A femtocell designed for homes can usually support between two and four mobile phone users simultaneously, while those designed for enterprises can support eight to 16 simultaneous users. These tiny base stations are normally placed indoors, where signals from outdoor cell sites can have difficulty reaching mobile phone users.
Once a user’s mobile phone that is initially connected to an outdoor cell site, known as a macrocell, detects a femtocell, it will automatically transfer to it. Femtocells are designed to work with only one mobile phone operator. Therefore, to maximize the full potential of a femtocell, household members or, in the case of business establishments, co-workers are encouraged to subscribe to the same mobile carrier.
Femtocells are most widely used in wideband code division multiple access (WCDMA) networks. However, other standards like the Global System for Mobile Communications (GSM), CDMA2000, Time Division Synchronous Code Division Multiple Access (TD-SCDMA), WiMAX, and LTE also support it.
A typical household femtocell has an operating radius of about 33 to 55 yards. Thus, in most cases, it can still be detected even while the user is outdoors.
There is no change in the way a user makes a call while connected to a femtocell. The only main difference is that signals received by the femtocell are sent to the mobile operator’s switching centers via the broadband IP network as encrypted data.