by Slovati @ dev.emcelettronica.com:
Femtocells are basically low-power wireless access points that operate inside licensed frequency bands for connecting standard mobile devices with a provider’s network, using a broadband connection such as the DSL or a cable connection (basically using the best Internet connection available at that point). A femtocell is therefore an indoor base station that allows you to make phone calls with your mobile cellular using the Internet service avaialble locally; it is able to do that because femtocell is a transceiver that operates on the same frequencies of mobile phones, all within a home or office. When you connect with a mobile device to a femtocell, therefore, you do not use directly the provider’s mobile network, but you use the base station.
The femtocell technology – [Link]