Mobile telephony

The mobile telephony indicates all the infrastructure of Télécommunication making it possible to use mobile phones (which one also calls mobile telephone, cell-phone one still natel in Suisse), allowing to telephone almost everywhere. This Technology, in particular thanks to constant progress of the electronic , developed considerably near the general public these ten last years, supplanting even in certain countries (Scandinavian mainly) the fixed telephone.

Mobile telephony is founded on the Radiotéléphonie, i.e. the transmission of the voice using Onde radio (Fréquence S in the band of the 900 and 1  800 MHz) between a base relay which covers a zone of several tens of kilometers of ray and the mobile phone of the user.

The first mobile systems functioned in mode Analogique. The terminals were of size important, only usable in the motor vehicles where they occupied part of the trunk and benefitted from the power supply of the vehicle.

The current mobile systems function in mode Numérique (the way is sampled, digitized and transmitted in the form of bits) and, progress of the Microélectronique made it possible to reduce the size of the mobile phones to a pocket format.

The bases of transmission are distributed on the territory according to a diagram of cells, each base uses a group of frequencies different from its neighbors, the same frequencies are re-used only at one sufficient distance so not creating a Interférence S.

The mobile systems are Standard ized to be compatible between the networks of the various countries and to be inter-connected with the networks of fixed telephony. There exists in the world two large standards of mobile systems, the standard IS41 of American origin (standard ANSI -41) and the standard GSM, defined in the Europe by the ETSI, most widespread.

To know on which basis to direct an incoming call, the mobile network exchanges periodically with the mobile phones of information in the form of messages of indication.

Standards

  • Mobile Advanced Phon System (AMPS): Analogical standard of first generation deployed with the the United States starting from 1976.
  • CDMA 2000 : Evolution of third generation (3G) of the CDMA (incompatible with the UMTS) mainly intended to be deployed in North America.
  • Code Division Multiple Access (CDMA): Normalizes of second generation derived from the standard ANSI-41, but whose patents belong to the company étatsunienne Qualcomm.
  • Enhanced Data Rates for Total Evolution (EDGE): Normalizes derived from GSM allowing a higher flow of data for a stationary user.
  • General Packet Radio operator Service (GPRS): Normalizes derived from GSM allowing a higher flow of data. It is often qualified 2,5G.
  • Mobile Global System for Communications (GSM): Numerical standard of second generation (2G) developped at the point by ETSI on frequency the band of the 900 MHz. An alternative called DIGITAL Communication System (DCS) uses the range of the 1  800 MHz. This standard is particularly used in Europe, in Africa, with the the Middle East and in Asia.
  • Radiocom 2000 : Analogical standard of first generation (1G) deployed in France by France Telecom.
  • mobile Universal telecommunications system (UMTS) or Wideband Codes Division Multiple Access (WCDMA): Evolution of third generation of the CDMA (incompatible with the CDMA-2000), supported by the Europe and the Japan.

Additional standards

  • I-mode: Protocol allowing to connect cellphones to Internet. The language used for the sites is a modified version of HTML called C-HTML.
  • Multi-media Messaging Services (ms): Multi-media mail service for cellphones.
  • Personal Ring Back Thunders (PRBT): Service which makes it possible to the subscribers of an operator to replace their ringing of usual waiting by musics
  • Short Message Service (SMS): Mail service for cellphones, allowing the sending of messages written of 160 characters maximum. This channel can also be used to transfer from the data (calling card, applicatives data for the Carte SIM, ringings, logos…)
  • Wireless application protocol (WAP): Protocol allowing to connect mobile phones to Internet. However, the language used for the sites intended for the WAP use a specific language of beaconing, the Wireless Markup Language or WML.

Various generations

Medical impact

The question arises as for the impact of the communication without wire on the health of the man. This technology uses the Micro-ondes which can prove to be dangerous when they exceed a certain power.

That relates to the antennas relay which emit uninterrupted and high power. They are installed in urban areas, and are often placed on the roofs of buildings (real, schools…). The people inhabitants near these antennas are permanently subjected to these waves, and no regulation exists concerning their sites compared to the dwellings.

Certain studies indicate that the mobile phones can also have an impact on health. Although emitting with low powers, they are, throughout the day with their users, often in their pockets and during their uses are stuck to the ear, close to the brain. However, the mobile phone adapts its power according to the distance which separates it from the antenna-relay: the weaker this distance is, the more the emitted power is weak.

In France

The fact that there are only three operators on the French market (Orange, Bouygues Telecom, SFR), implies that the cost of mobile telephony in France is particularly high compared to tariff applied in the adjoining countries.

The three French physical networks are now also used by virtual mobile operators (MVNO), appeared since 2005, of which the number is in strong increase (an in May 2007 dozen).

The procedure of portability of the numbers between operators, intended to reinforce competition, was simplified and shortened on May 21st, 2007, allowing a change of operator in 10 days.

In the Antilles and in Guyana there are 3 operators (Caribbean Orange, Digicel and Only) and an operator of virtual mobile network (Mobile Trace) using the network of Digicel.

Many mobiles in France

See too

External bonds

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