UMA (GAN, Generic Access Network, Unlicensed Mobile Access)

Unlicensed Mobile Access is a technology that allows a UMA capable mobile phone to seamlessly switch back and forth between mobile phone networks and local wireless networks. WiFi and Bluetooth are commonly used for the local wireless part of the system. Simply possessing a UMA capable phone does not mean that a subscriber can make use of UMA services since the system requires back-end support from the carrier. UMA is particularly useful in remote areas where mobile phone coverage is poor, as well as inside of buildings where the network signal might not be able to penetrate building walls. In the US, T-Mobile was the first carrier to start offering UMA services. UMA has been officially ratified by the 3GPP and has been renamed GAN, or Generic Access Network, though most often the technology is still referred to by the UMA name.