Universal Mobile Telecommunication System
Work on 3G broadband systems commenced in 1985 and was carried out under the auspices of the International Telecommunication Union (ITU). It was decided that the new system, eventually named IMT-2000 (International Mobile Telecommunications), would provide the following standards [1–3]:
- Transmission rates:
- transfer of up to 2 mbps inside of buildings and for slowly moving mobile stations (at the speed of less than 10 km/h);
- 384 kbps for terminals moving with a speed of up to 120 km/h in built-up areas;
- 144 kbps in non-built-up areas and in the case of fast moving terminals.
- Access to the Internet.
- Transmission in circuit switching operation and packet switching operation modes.
- Services in real time and multimedia and localization services.
- Simultaneous invocation of different services.
- Global roaming.
- Availability of services independently of the current localization of the subscriber and the radio interface used.
- High level of security of sent data.
- Smooth transition from the second generation systems to that of 3G.
Provision of standards for a system that would meet the above prerequisites was assigned to regional standardization organizations whose activity was mainly focused on working out a radio interface for the ground segment of the system. Eventually, three different standards for radio interface were agreed to be included in the IMT-2000 :
- UMTS terrestrial radio access (UTRA) — broadband CDMA ...