The UMTS standard recognizes several different access and modulation methods: Time Division Multiple Access( TDMA) and Wideband Code Division Multiple Access(WCDMA) with Frequency Division Duplex ( FDD) and Time Division Duplex( TDD). TDMA is to be used for voice transmission only in the first few years. In contrast, WCDMA with FDD has the advantage that several subscribers can use one channel simultaneously.
UMTS provides for data transmission rates of384 kbit/s for mobile applications and up to 2 Mbit/s for connections to stationary terminals. Transmission takes place in the frequency ranges between 1.900 GHz and 2.025 GHz and between 2.110 GHz and 2.200 GHz. The upstream range is divided into a 20 MHz wide frequency band between 1.900 GHz and 1.920 GHz, in which the TDD method is used, and another upstream band between 1.920 GHz and 1.980 GHz, which is reserved for Frequency Division Duplex (FDD).
The downstream range is between 2.010 GHz and 2.025 GHz for TDD transmission and between 2.110 GHz and 2.170 GHz for FDD transmission.
In addition, the frequency range between 1.980 GHz and 2.010 GHz is reserved for Mobile Satellite Services( MSS), as is the range between 2.170 GHz and 2.200 GHz for satellite downstream. These satellite frequency bands could be used when terrestrial transmission is not possible. This means that UMTS can also be used by global travelers worldwide: terrestrially or via satellite.