A little more than two decades have passed since the first mobile phones were introduced, but mobile communications have already undergone significant changes. Systems of the first generation, based on the analog principle, were used exclusively for telephone communications and only later acquired some basic services. Second-generation systems, including the GSM standard, provide improved transmission quality and signal protection, additional services, low-speed data transmission, and for GSM systems – an automatic service, so-called. roaming for the convenience of the subscriber’s movement across different countries and continents.
Soon after the advent of the second generation of mobile systems, preparations began to design next generation mobile standards. The developments were carried out both at the regional level (ETSI, the RAINBOW project from ACTS, US Joint Technical Committee, Japanese ARIB) and at the global level – ITU (International Telecommunications Union), which resulted in the creation in 1985 of an initiative group, which in 1996 was renamed into IMT-2000. The number ‘2000’ is intended to denote the technology of the new millennium and the new frequency range intended for this technology – 2 GHz. Different projects have proposed different paths for the transition to third generation systems. Within the framework of each project, two development options were mainly considered: a gradual transition from the currently operating systems and a “leap” leap. Most were inclined towards the need for gradual integration, which was reflected in the work of IMT 2000.
The third generation technology (3G) provides high-quality voice and image transmission (the speed is expected to reach 2 Mbps instead of 9.6 Kbps available today), multimedia content and Internet access, as well as data exchange between a mobile phone and a computer. At the same time, 3G technologies should improve the quality of service of second generation networks by adding many new services to them.