UMTS Frequency Bands: 2100 MHz and 900 MHz

Which UMTS bands a device must support depends on where it will be used — Band I at 2100 MHz is the core, 900 MHz is the rural layer.

UMTS Band I runs at 2100 MHz: 1920–1980 MHz for the uplink from the phone, and 2110–2170 MHz for the downlink to the phone. It was the launch band of the first commercial 3G service, NTT DoCoMo's FOMA network in Japan in October 2001.

The radio on that band is W-CDMA: a 5 MHz carrier with a 3.84 Mcps chip rate. Every user in the cell shares the carrier, which is why real throughput falls below the headline speed classes when a cell is busy.

Lower frequencies travel further and penetrate buildings better, so carriers refarmed 900 MHz spectrum from 2G to 3G to widen rural coverage. A handset that supports only Band I can show full bars in a city and nothing at all in the countryside.

Reading a spec sheet is straightforward once you know the vocabulary: look for 'UMTS' or 'W-CDMA' followed by band numbers or frequencies. Band I may appear as '2100' or 'Band 1', and the 900 MHz layer as '900' or 'Band 8'.

Before keeping a 3G device for a given country, match two things: the band list on the spec sheet against the carrier's deployed bands, and the carrier's shutdown date against your plans. The dates are collected on the 3G Shutdown Schedule page, and the speed each layer can carry is broken down on 3G Speeds Explained.

• Band I — 2100 MHz: 1920–1980 MHz uplink, 2110–2170 MHz downlink
• 900 MHz — refarmed from 2G for wider rural coverage
• 5 MHz carrier, 3.84 Mcps chip rate on W-CDMA
• Check the spec sheet for 'UMTS' or 'W-CDMA' band numbers

Further reading

• 3G Speeds Explained: From 144 kbps to 42 Mbps
• 3G Shutdown Dates and What Replaces It