UMTS stands for the Universal Mobile Telecommunication System. The UMTS network is a wireless 3G (third generation) network that provides high bandwidth voice and data service to users of mobile devices. 3G is a category of digital cellular radio systems developed under the standard IMT-2000 (International Mobile Telecommunications-2000).
The 3G systems were created with the intention of allowing users to have global mobility with services including Internet, data, messaging, paging, and telephony. The idea was to provide consistent service to roaming mobile customers anywhere in the world. A combination of terrestrial-based wireless services and satellite transmissions were designed to provide this availability.
The UMTS network is also called 3GSM (Global System for Mobile communications) because it evolved from that system. The air interface for the UMTS network is based on WCDMA (Wideband Code Division Multiple Access) and includes the HSPA (High Speed Packet Access) specification. The Internet protocol was based on GPRS (General-Packet Radio Service), which evolved into EDGE (Enhanced Data rates for Global Evolution, a.k.a. GSM Evolution), both of which were considered 2.5G standards.
There are several ways in which the UMTS network differs from prior systems. One way is that previously, cellular systems were mainly circuit-switched, while UMTS is packet-switched. It also has higher bandwidth than previous systems.
The services provided by UMTS have three different Quality of Service (QoS) target data rates. These are 144 kbps (kilobytes per second) for satellite use and outdoor rural use; 384 kbps for use in outdoors in urban environments; and 2048 kbps for indoor use and outdoor use that is low-range. There are four specified classes of serve. The conversational class includes voice services, video gaming, and video telephony. The streaming class includes multimedia, webcasting, and video on demand. The interactive class includes web browsing, accessing databases, and network gaming, while the background class includes email, downloading, and SMS (Short Message Service) messaging.
LTE (Long Term Evolution) has developed out of UMTS. LTE and WiMAX (Worldwide Interoperability for Microwave ACceSs) are the two developments of 4G wireless networks, as of 2010. Whereas LTE started with the IMT-2000 standard that underpins the UMTS network and is sometimes referred to as UMTS LTE, while WiMAX draws on other standards.