GSM (Global System for Mobile Communications)

GSM (Global System for Mobile Communications)

GSM (Global System for Mobile Communications)

GSM (Global System for Mobile Communications) is a technology that is digital cellular communications. GSM technologies are widely applied to mobile communications, especially mobile phones. This technology utilizes the microwave and signal transmission divided by time, so the signal information sent will reach its destination. GSM become the global standard for mobile communications as well as the technology provider of the most widely used by people all over the world.

• GSM Network Architecture

GSM Network Architecture

• The historial and development of GSM (Global System for Mobile Communications)

 Mobile communication technology's already developed in the 1980s, including the C-NET system that was developed in Germany and Portugal by Siemens, RC-2000 system developed in France, NMT system developed in the Netherlands and the Scandinavian by Ericsson and TACS system in UK. However, as the technology is still used analog create a regional system so that the system between states with one another are not mutually compatible, it makes user mobility limited to a particular area of ​​technology systems (can not roam between countries).

Phone Mobile 1980s

Analog technology incompatible with the development of European societies are increasingly dynamic, limitations solved with, an organization formed in 1982 in the European countries to determine the cellular communication standards that can be used throughout Europe, it's called Group Special Mobile (GSM ). This organization is a pioneer of digital cellular technology that became known as GSM (Global System for Mobile Communication).
GSM started in mid 1991 and used as the standard for mobile telecommunications throughout Europe by ETSI (European Telecommunications Standards Institute). GSM commercialized at the beginning of the last quarter of 1992 because of GSM technology is complex and needs more in-depth discussion to be used as a standard. September 1992, type approval standards for mobile phones agreed to consider and include test items in producing GSM. At the beginning of the operation, GSM has anticipated the growing amount of users is very fast and direction of service per area is high, so the direction of the development of GSM technology is DCS (Digital Cellular System) in the 1800 MHz frequency allocation. With these frequencies, will achieve greater subscriber capacity per unit cell. Furthermore, with a smaller cell that can reduce the transmit power of mobile phones, so the radiation hazard arising against organ head will be reduced. GSM later spread to Asia and America. Indonesia's first analog mobile phone system or called AMPS (Advances Mobile Phone System) and NMT (Nordic Mobile Telephone). But with a standard mobile communication systems, analog systems slowly disappearing in Indonesia and Europe. GSM users also increasing. the end of 2005, GSM subscribers worldwide reached 1.5 trillion. up to now grow as GSM mobile telecommunications system widely used throughout the world.

• GSM technical specifications

GSM was originally designed to operate at 900 MHz for Europe. uplinks frequency was used frequencies 890-915 MHz, 935-960 MHz frequency downlinksnya. Bandwithnya 25 Mhz (915-890 = 960-935 = 25 MHz), and the channel width 200 Khz. Of the two, the diperoleh125 channels, 124 channels for voice and one channel for signaling. 124 the number of channels is not sufficient to meet the requirement because of the rapid increase in the number of users. To fix this, the regulator GSM in Europe tried using additional frequency bands for GSM 1800 MHz frequency range with frequency 1710-1785 MHz for uplinks and 1805-1880 MHz frequency to frequency downlinks. GSM is known as GSM 1800, which provides a bandwidth of 75 MHz (1880-1805 = 1785-1710 = 75 MHz). With 200 Khz channel width, while GSM at 900 MHz, then the GSM 1800 will be available as much as 375 channels. GSM standards and is being used for railway communication, which became known as GSM-R, in Europe.