Evolution to 3G and UMTS Service Overview

Third generation (3G) systems, such as the Universal Mobile Telecommunications System (UMTS) or cdma 2000, are the result of evolution from voice optimised analogue systems like the North American Advanced Mobile Phone System (AMPS), Nordic Mobile Telephone System (NMT) or UK based Total Access Communication System (TACS). The relatively poor spectral efficiency, security and limited roaming of these first generation (1G) systems led to second generation (2G) systems such as the European Global System for Mobile Communication (GSM) and digital AMPS
(D-AMPS) from North America, which also produced cdma One, a narrowband CDMA system which demonstrated clearly the potential of code division multiple access (CDMA) for mobile communication. GSM has become a de facto global standard and under Phase 2+ evolution can offer packet-switched data with the General Packet Radio Service (GPRS) up to 115.2kbps and ultimately 384kbps with GPRS + EDGE (Enhanced Data for Global Evolution). With High Speed Circuit Switched Data (HSCSD), circuit-switched data to 57.6kbps can be supported. The CDMA technique has been retained for the major 3G systems, but in wideband form (W-CDMA) to
support much higher user data rates. This will permit multi-media services to operate with high quality and make possible bandwidth on demand for mobile communication. Both CS and PS data are supported, with user rates up to 2.048Mbps peak (likely to rise in the future). 3G systems also promise better spectral efficiency, security and roaming.

Evolution to 3G and UMTS Service Overview pdf

source : m2vtelecom.blogspot.com