Общие принципы сотовой связи

Not far behind Europe and America, the self-proclaimed his concept of a "personal communications Services" - PCS (Personal Communication Services). Its aim was 50%coverage of the country's population by the year 2000. For realization of this concept the Federal communications commission of the USA has allocated three frequency plot in the range of 1.9-2.0 Ghz (broadband PCS) and one part in a range of 900 Mhz (narrow-band PCS).

In 1990, the american Industrial association in the field of communications TIA (Telecommunications Industry Association) approved the national standard is-54 digital cellular communication. This standard became more known under the abbreviation D-AMPS or ADC. Unlike Europe, in the united states have not been identified new frequency ranges, so the system must operate in the frequency band, the common with analog standard AMPS. At the same time with the american company Qimlcomm the beginning of active development-development of a new standard of cellular communication, based on the technology of noise-type signals and code division of channels- CDMA (Code Division Multiple Access).

In 1991, appeared in Europe the DCS-1800 Digital Cellular System 1800 Mhz), created on the basis of GSM standard. Britain immediately adopted it as the basis for the development of the above mentioned concept of the PCN, that was the beginning of a victorious march of this standard on the continents of the globe.

In the development of cellular communication of Europe and the united states was not far behind and Japan. In this country has developed its own standard of cellular communication of the JDC (Japanese Digital Cellular), similar in its characteristics to the american standard D-AMPS. Standard JDC was approved in 1991. The ministry of posts and telecommunications of Japan.

In 1992, in Germany has entered into commercial operation the first system of cellular communication of GSM standard.

In 1993 in the united states after a series of successful tests of the Industrial association in the field of communications TIA adopted the standard CDMA as an internal standard for digital cellular communication, calling it the is-95. In September 1995 in hong Kong was launched commercial operation of the first network of the standard is-95.

In 1993, in the united kingdom entered into operation of the first network DCS-1800 Ope-tm-2-Ope, which now has more than 500 thousand subscribers.

What is cellular communication, Russia recognized only at the sunset of perestroika. In St. Petersburg and then in Moscow and the system of standard NMT-450J (a modified version of the standard NMT-450). But the adoption in 1994 of the concept of development of land mobile networks has become a powerful catalyst for the further development of cellular communication in the national scale. And if with the introduction of standard NMT and AM PS our country fell behind for ten years, the proclamation of the GSM standard as one of the two federal standards (NMT and GSM) reduced the time gap until about three years.

The precise orientation of the progressive world technologies gives an opportunity for Russia does not lag behind the leading countries of the world in the development of modern systems of mobile radio communication. Not lagging behind Russia and in the field of introduction of the progressive CDMA standard. Conditions for the development of CDMA networks in Russia are defined by the order of the Ministry of communications of the RUSSIAN federation № 18 of February 24, 1996., where it is stated that the CDMA network focused on providing services of fixed subscribers. But allow for the possibility of their application from cell to cell, that is, are given limited mobility of subscribers. The first network of standard CDMA began operating in Chelyabinsk, it is planned to introduce CDMA networks in Moscow and St. Petersburg.

Further development of the cellular mobile communication is carried out in the framework of the project creation of the systems of the third generation, which will differ a unified system of radio access, linking the existing cellular and "бесшнуровые" system with information services in XXI century. They will have the architecture of the unified network and provide communication subscribers in a variety of conditions, including moving transport, residential premises, offices, etc. In Europe, this concept, known as UMTS (universal mobile telecommunications), includes the consolidation of the functionality of existing digital communication systems into a single system of the third generation FPLMTS (Future Public Land Mobile Telecommunications System), which should become the result of the integration of wireless access systems and terrestrial wireless connection with the provision of subscribers of standardized services of mobile communication. The work on creation of the international system of general use mobile communication FPLMTS are the International telecommunication union. For it was determined the frequency range of 1 to 3 Ghz, which will be highlighted in a band width of 60 Mhz for fixed stations, and 170 Mhz for mobile stations. However, it soon became clear that, despite the widespread introduction of systems of terrestrial communications and the use of roaming, a great part of the territory of the globe, including the world's oceans, is unattainable for FPLMTS. It is obvious that the global coverage is only possible with the help of communication satellites, and therefore, when developing a uniform standard, providing global connectivity, can not do without the satellite technologies. Therefore, the requirements of the unified system of mobile communication were formulated in the framework of the new program IMT-2000 (International Mobile Telecommunications).

The new name is no longer available, the term "Land " (land), but there is the figure of 2000, which indicates the estimated date of the adoption of the standard, and the value of the frequency (2000 Mhz), in the area of which is planned to allocate frequency resources for terrestrial and satellite communication systems. The structure of the radio interfaces for IMT-2000 are presented in fig. 2.2.

The fundamental difference of technology 3rd generation from the previous –

 ПЕРЕВЕСТИ НОРМАЛЬНО!.