UMTS (Universal Mobile Telecommunications System)

UMTS, the Universal Mobile Telecommunications System, is one of the main third-generation (3G) mobile phone standards. It was developed as a successor to the second-generation GSM system to provide higher data rates alongside voice calls, enabling mobile internet access, video calling and other data services. UMTS was standardised within the framework set by international cooperation among telecommunications bodies and was deployed by network operators in many countries.

The defining technical feature of UMTS is its radio access method, Wideband Code Division Multiple Access (WCDMA). In CDMA techniques, many users share the same frequency band at the same time, and their signals are separated by unique codes rather than by being assigned different time slots or frequencies. This contrasts with GSM, which combines frequency division and time division multiple access to give each call a slot. The wideband approach of WCDMA spreads each signal across a broad channel, supporting higher data throughput.

UMTS networks typically built on existing GSM infrastructure, and handsets were often designed to work with both so calls could continue where 3G coverage was unavailable. Over time, enhancements raised data speeds further, and UMTS was eventually succeeded by faster fourth-generation and later mobile technologies. It nonetheless marked an important step in the move from voice-centred mobile networks toward systems built around mobile data and the wireless internet.

Frequently asked questions

What is UMTS?

UMTS is a third-generation mobile telephone standard that succeeded GSM, offering higher data rates for mobile internet, video calling and other services alongside voice calls.

How does WCDMA differ from GSM's access method?

WCDMA separates users by unique codes sharing a wide frequency band, while GSM divides access by time slots and frequencies. The wideband approach supports higher data throughput.

How does UMTS relate to GSM?

UMTS was built as the 3G successor to the 2G GSM system, often sharing infrastructure, and many phones supported both so service continued outside 3G coverage.