How the cellular communication works. The principle of the cellular connection that is a cellular communication

cellular

cellular, mobile communication network - one of the types of mobile radio, which is based on cell network. Key feature It is that the total coverage area is divided into cells (honeycombs), which are determined by the coating zones of individual base stations (BS). The cells partially overlap and together form a network. On the ideal (smooth and without development) the surface of the coating zone of one BS is a circle, so the network composed of them has the type of honeycomb with hexagonal cells (cells).

The network is made up in the space of transcerementators operating in the same frequency range, and switching equipment, which allows to determine the current location of mobile subscribers and ensure the continuity of communication when the subscriber is moved from the zone of one transceiver to the other area.

History

The first use of mobile telephone radio communications in the United States refers to 1921: Detroit police used one-sided dispatching in the 2 MHz range to transfer information from the central transmitter to receivers installed on automaints. In 1933, the New York Police began to use the bilateral mobile telephone radio system also in the 2 MHz band. In 1934, the US Federal Communications Commission allocated 4 channels for telephone radio communications in the range of 30-40 MHz, and in 1940, about 10 thousand police cars were already telephone radio communications. All these systems used amplitude modulation. Frequency modulation began to be applied from 1940 and by 1946 completely supplanted amplitude. The first public moving radiotelephone appeared in 1946 (St. Louis, USA; Bell Telephone Laboratories), it used the range of 150 MHz. In 1955, a 11-channel system began to operate in the 150 MHz range, and in 1956 - a 12-channel system in the range of 450 MHz. Both of these systems were simplex, and a manual switching was used in them. Automatic duplex systems began to work accordingly in 1964 (150 MHz) and in 1969 (450 MHz).

In the USSR in 1957, the Moscow engineer L. I. Kuryovovich created an experimental sample of the wearable automatic duplex mobile radio telephone LC-1 and the base station to it. Mobile radiotelephone weighed about three kilograms and had a radius of 20-30 km. In 1958, Kupriyanovich creates improved models of the device weighing 0.5 kg and the size of a cigarette box. In the 1960s Hristo Bocharov in Bulgaria demonstrates its prototype of a pocket mobile radio telephone. At Interior Enterprise-66, Bulgaria presents a kit for organizing local mobile communication from pocket mobile phones RAT-0.5 and ART-0.5 and the RATTS-10 base station, which provides a connection of 10 subscribers.

At the end of the 50s in the USSR, the development of the Altai automotive radiotelephone system, introduced into trial operation in 1963, the Altai system originally worked at a frequency of 150 MHz. In 1970, the Altai system worked in 30 cities of the USSR and a range of 330 MHz was allocated for it.

Similarly, with natural differences and at a smaller scale, the situation in other countries has developed. So, in Norway, public telephone radio communications was used as marine mobile communications since 1931; In 1955 there were 27 coastal radio stations in the country. Ground mobile communication began to develop after the Second World War in the form of private hand-switched networks. Thus, by 1970, mobile telephone radio communications, on the one hand, has already been widely widespread, but on the other, it clearly did not have time for rapidly growing needs, with a limited number of channels in rigidly defined frequency bands. The output was found in the form of a cellular system, which made it possible to dramatically increase the capacity due to the reuse of frequencies in the system with a cellular structure.

Cellular systems

Individual elements of the cellular system existed before. In particular, some similarity of the cellular system was used in 1949 in Detroit (USA) Taxi dispatch service - with repeated frequencies in different cells at manual switching channels by users in the places staged in advance. However, the architecture of the system, which today is known as a cellular system, was set out only in the technical report of the Bell System, submitted to the US Federal Communications Commission in December 1971. From this time, the development of a cellular communications itself begins.

In 1974, the US Federal Communications Commission adopted a decision on the allocation of frequency bands at 40 MHz in the 800 MHz band; In 1986, another 10 MHz in the same range was added to it. In 1978, tests of the first experienced cellular system for 2 thousand subscribers began in Chicago. Therefore, 1978 can be considered a year of the beginning of the practical application of cellular communication. The first automatic commercial cellular system was also put into operation in Chicago in October 1983. Aperican Telephone and Telegraph (AT & T). In Canada cellular Used since 1978, in Japan - from 1979, in Northeurway countries (Denmark, Norway, Sweden, Finland) - from 1981, in Spain and England - from 1982 as of July 1997, cellular communication Worked more than 140 countries of all continents, serving more than 150 million subscribers.

The first commercially successful cellular network was the Finnish AutoRADIOPUHELIN (ARP) network. This name is translated into Russian as a "car radio telephone". Launched in 1971, it reached 100% of the coverage of the territory of Finland in 1978, and in 1986 there were more than 30 thousand subscribers. The network at a frequency of 150 MHz worked, the size of the cell is about 30 km.

Cellular Principle

The main components of the cellular network are cell phones and base stations that usually have on the roofs of buildings and knitting. Being included cellular telephone Listenins the air, finding a base station signal. After that, the phone sends its own unique identification code. The phone and station support constant radio contacts, periodically exchanged packages. The phone connection with the station can go through analog protocol (AMPS, NAMPS, NMT-450) or digital (DAMPS, CDMA, GSM, UMTS). If the phone comes out of the base station (or the quality of the service cell's radio signal is deteriorating), it sets off with the other (eng. handover.).

Cellular networks may consist of basic stations of a different standard, which allows you to optimize the operation of the network and improve its coating.

Cellular networks of different operators are connected to each other, as well as with a stationary telephone network. This allows subscribers of one operator to make calls to subscribers of another operator, from mobile phones to stationary and from stationary to mobile.

Operators may conclude roaming treaties. Thanks to such contracts, the Subscriber, being outside the coverage area of \u200b\u200bits network, can make and receive calls through a network of another operator. As a rule, this is carried out on high rates. The possibility of roaming appeared only in 2G standards and is one of the main differences from 1G networks.

Head of the Regional Journalism Club Irina Yasina recalls:

By July 1997, the total number of subscribers in Russia amounted to about 300 thousand. For 2007, the main protocols of the cellular communication used in Russia are GSM-900 and GSM-1800. In addition, the CDMA-network works are also working, in the CDMA-2000 standard, it is imt-MC-450. Also GSM operators are a smooth transition to the UMTS standard. In particular, the first fragment of the network of this standard in Russia was commissioned on October 2, 2007 in St. Petersburg by MegaFon.

IDC, based on the study of the Russian cellular market, concluded that in 2005 the total duration of conversations on cell phone residents of the Russian Federation reached 155 billion minutes, and text messages 15 billion pieces were sent.

According to the data of the British research company Informa Telecoms & Media for 2006, the average cost of a cellular communication for the consumer in Russia was $ 0.05 - this is the lowest figure of the G8 countries.

In December 2007, the number of cellular users in Russia increased to 172.87 million subscribers, in Moscow - to 29.9, in St. Petersburg - to 9.7 million. The level of penetration in Russia - up to 119.1%, Moscow - 176%, St. Petersburg - 153%. In December 2011, the level of penetration in Russia - up to 156%, Moscow - 212.1%, St. Petersburg - 215.6%. The share of the market of the largest cellular operators for December 2007 was: MTS 30.9%, VimpelCom 29.2%, MegaFon 19.9%, other operators 20%.

According to the research company J "Son & Partners, the number of SIM cards registered in Russia as of the end of November 2008 reached 183.8 million. This figure is due to the absence subscription fee on popular tariff plans Russian cellular operators and low network connection price. Subscribers in some cases have SIM cards of different operators, and they can not use for a long time, or use one SIM card in a service mobile phone, and the other is for personal conversations.

In Russia in December 2008, there were 187.8 million cellular users (by the number of SIM cards). The level of cellular penetration (the number of SIM cards per 100 inhabitants) was thus 129.4%. In the regions, without taking into account Moscow, the penetration rate exceeded 119.7%.

The penetration rate at the end of 2009 reached 162.4%.

As of April 2010, the market share in Russia by subscribers: MTS - 32.9%, megaphone - 24.6%, VimpelCom - 24.0%, Tele2 - 7.5%, other operators - 11.0%

Cellular services

Cellular operators provide the following services:

• Voice call;
• AON (automatic number determinant) and antiaon;
• Reception and transmission of multimedia messages - images, melodies, video (MMS service);
• Access to the Internet ;
• Video call and video conferencing

see also

Notes

Links

• The base of the cellular network - how to build base stations - a review article on the site 3dnews.ru (Rus.)
• Cellular Communication Center - View from the inside - Overview article on the site 3Dnews.ru (Rus.)
• The main indicators of the development of telephone communications and mobile communication (at the end of 2009)

Wikimedia Foundation. 2010.

Watch what is "cellular communication" in other dictionaries:

- (English Cellular Phone, mobile radio relay), type of radiotelephone communication in which the end devices are mobile phones (see mobile phone) are connected to each other with a cellular network of a set of special transceivers ... ... encyclopedic Dictionary

One of the types of mobile radio, which is based on a cellular network. The key feature is that the total coverage area is divided into cells (cells), which are determined by the coating zones of individual base stations (BS). Sota partially ... ... Business Terms Dictionary

Cellular communication of the third generation - Third-generation cellular networks (3rd generation, or 3G) operate at the frequencies of about 2 gigahertz and provide data transmission at speeds up to 2 megabits per second. Such characteristics allow you to use a mobile phone, in ... ... Encyclopedia Newsmakers

Ekaterinburg 2000 Type Cellular Operator Location ... Wikipedia

The article contains errors and / or typos. It is necessary to check the content of the article for compliance with the grammatical standards of the Russian language ... Wikipedia

Useful services and services that can be connected along with the tariff or already in the process of use.

Transferring minutes, GB and SMS for next month

The remains of the main minutes of minutes, SMS and GB included in the monthly fee are transferred in the current estimated period. Transferred residues can be used during the next settlement period. First of all, the transferred remains of minutes, SMS and GB are spent, hereinafter - services packagesincluded in the tariff plan. Transfer is possible only with a timely monthly fee set for your tariff plan.

Not available on the tariff plans "A whole story", "Family Story" and "Infinite Story"

Exchange of minutes on GB

Get more Internet by changing unused minutes from the package for additional gigabytes.

You can exchange moments:

The main package included in the tariff;

Received within the transfer of residues.

Exchange rate:

• 1 minute \u003d 10.24 MB;
• 10 minutes \u003d 102.4 MB;
• 100 minutes \u003d 1 GB

The service is free, but is provided only if the subscription fee is written for the connected tariff.

The service is not provided at the time of the options "Add Traffic" / "500mb +"

First of all, Internet traffic from the transferred package is consumed, after its exhaustion - from the main Internet traffic package.

The volume of Internet traffic obtained in exchange for minutes is transferred to the next billing period, but not more than a two-time size of the main package provided according to the terms of the tariff plan. When changing the tariff plan, the unsighted Internet traffic burns.

You can use the service throughout Russia, with the exception of the Republic of Crimea and G. Sevastopol.

Not available on tariff plans: " New story. In the network "," a whole story "," Family Story ";" SuperSimka S "," For Unlimited "and" Infinite Story ", including archived.

Learn the number of minutes available for the exchange of minutes * 108 # See the minutes of the exchange of minutes * 108 * 0 # exchange moments on GB * 108 * Number of minutes #

Urban number without surcharge

Available in the tariffs "Family Story", "History" and "Infinite Story"

Cellular communication has recently entered our daily life so firmly, it is difficult to submit modern society without it. Like many other great inventions, the mobile phone has greatly influenced our life, and for many of its spheres. It is difficult to tell what the future would be if it were not for this convenient type of communication. Surely the same as in the film "Back to the Future-2", where there are flying cars, hover boards, and much more, but there is no cellular!

But today in a special report for will not be a story about the future, but about how modern cellular communication works and works.

In order to learn about the work of modern cellular communication in 3G / 4G format, I asked for a visit to the new federal operator Tele2 and spent a whole day with their engineers who explained to me all the subtleties of data transmissions through our mobile phones.

But I will first tell a little about the history of cellular communication.

The principles of the work of the unproductive communication were tested almost 70 years ago - the first public moving radiotelephone appeared in 1946 in St. Louis, the United States. In the Soviet Union, an experienced sample of a mobile radio telephone was created in 1957, then scientists of other countries created such devices with various characteristics, and only in the 70s of the last century in America, modern principles of cellular communication were identified, after which its development began.

Martin Cooper - the inventor of the prototype of a portable cell phone Motorola Dynatac weighing 1.15 kg and dimensions of 22,5x12,5x3.75 cm

If in Western countries by the mid-90s of the last century, the cellular communication was common everywhere and most of the population used it, then in Russia she just began to appear, and became accessible to everyone just over 10 years ago.

Bulky brick-like mobile phones who worked in the formats of the first and second generations went down to history, giving way to smartphones with 3G and 4G, the best voice communication and high speed of the Internet.

Why is the connection called cellular? Because the territory on which communication is associated is divided into separate cells or cells, in the center of which base stations (BS) are located. In each "honeycom", the subscriber receives the same set of services in certain territorial boundaries. This means that moving from one "honeycomb" to another, the subscriber does not feel the territorial attachment and can freely use the services of communication.

It is very important that there is a connection continuity when moving. This is ensured by the so-called Handover (handover), in which the connection established by the subscriber as it would be picked up by adjacent cells along the relay, and the subscriber continues to talk or dig in social networks.

The entire network is divided into two subsystems: the subsystem of base stations and the switching subsystem. Schematically, it looks like this:

In the middle of the "honeycomb", as mentioned above is the base station, which usually serves three "honeycombs". Radio signal from the base station is emitted through 3 sector antennas, each of which is directed to its "honeycomb". It happens that on one "honeycom" several antennas of one base station are directed at once. This is due to the fact that the cellular network operates in several ranges (900 and 1800 MHz). In addition, this base station may present equipment of several generations of communication (2G and 3G).

But on the BS TELE2, there is only the third and fourth generation equipment - 3G / 4G, since the company decided to abandon old formats in favor of new, which help avoid voice breaks and provide more stable Internet. Priséouts of social networks will support me that in our time the speed of the Internet is very important, 100-200 Kb / s no longer enough, as it was a couple of years ago.

The most familiar placement of the BS is a tower or mast, built specifically for it. Surely you could see the Red-White Ties BS somewhere in remoteness from residential buildings (in the field, on the hill), or where there are no high buildings nearby. As this, which is visible from my window.

However, in the conditions of urban areas it is difficult to find a place to place a massive structure. Therefore, in large cities, base stations are placed on buildings. Each station catches a signal from mobile phones at a distance of up to 35 km.

These are antennas, the BS equipment itself is in the attic, or in the roof container, which is a pair of iron cabinets.

Some basic stations are located where you can not even guess. How, for example, on the roof of this parking lot.

The BS antenna consists of several sectors, each of which takes / sends a signal to its side. If the vertical antenna communicates with telephones, the round connects the BS with the controller.

Depending on the characteristics, each sector can serve up to 72 calls at the same time. The BS may consist of 6 sectors, and to serve up to 432 calls, but usually sets fewer transmitters and sectors at stations. Cellular operators, such as Tele2, prefer to put more BS to improve the quality of communication. As I was told, here the most modern equipment is used: Ericsson base stations, a transport network - Alcatel Lucent.

From the base stations subsystem, the signal is transmitted towards the switching subsystem, where the connection with the desired subscriber is established. In the switching subsystem, there are a number of databases in which information about subscribers is stored. In addition, this subsystem is responsible for security. If you say easier, then the switch is performed the same functions as the girls operators who previously combined you with the subscriber, only now all this happens automatically.

Equipment for this base station is hidden in this iron cabinet.

In addition to conventional, there are also mobile variants of base stations located on trucks. They are very convenient to use during natural disasters or in places of mass accumulation of people (football stadiums, central squares) for the time of holidays, concerts and various events. But, unfortunately, due to problems in the legislation of widespread use, they have not yet found.

To ensure optimal coating with a radio signal at the ground level, base stations are designed in a special way, because despite the range of 35 km. The signal does not apply to the height of the aircraft flight. However, some airlines have already begun to install small base stations in their sides, providing cellular communication within the aircraft. Such BS is connected to the ground cellular network using the satellite channel. The system is complemented by the control panel, which allows the crew to enable and disable the system, as well as individual types of services, for example, turn off voice over night flights.

I also looked into the Tele2 office to see how experts control the quality of cellular communication. If a few years ago, such a room would be hung to the ceiling by monitors showing network data (loading, network accident, etc.), then over time, the need for such a number of monitors has dropped.

Technology over time has been strongly developed and enough such a small room with several specialists to watch the work of the entire network in Moscow.

A little species from Tele2 office.

At the meeting of the company's employees, plans to seize the capital) Since the beginning of the construction, until today Tele2 managed to cover all Moscow to its network, and gradually conquers the Moscow region, launching more than 100 base stations weekly. Since I live now in the area, it is very important for me. So that this network came as quickly as possible in my town.

The company's plans for 2016. Ensuring high-speed communication in the subway at all stations, at the beginning of 2016, Tele2 is present at 11 stations: Communication 3G / 4G standard on Borisovo metro station, "Business Center", "Kotelniki", "Lermontovsky Prospect" , Troparevo, Shipivskaya, Zyablovko, 3G: "Belorusskaya" (ring), "Spartak", "Pyatnitsky highway", "Zhulebino".

As I said above, Tele2 abandoned GSM format in favor of third and fourth-generation standards - 3G / 4G. This allows you to install 3G / 4G base stations with a larger frequency (for example, within the Moscow Ring Road, it is about 500 meters away from each other) to ensure a more stable connection and high speed. mobile InternetWhat was not in the networks of previous formats.

From the office of the company, I go to one of the points of engineers from Nikifora and Vladimir engineers, where they need to measure the speed of communication. Nikifor stands opposite one of the mast on which equipment is installed to provide communication. If you look closely, notice a little further to the left of another such mast, with the equipment of other cellular operators.

Oddly enough but cellular operators Often allow their competitors to use their tower facilities to place antennas (naturally on mutually beneficial terms). This is due to the fact that the construction of the tower or mast - expensive pleasure, and this exchange allows you to save a lot of money!

While we measured the speed of communication, Nikifora several times passersby grandmothers and uncle asked whether he was not a spy)) "Yes, the wast radio" Freedom "!).

The equipment actually looks unusual, in his mind you can assume anything.

Specialists from the company a lot of work, if we consider that in Moscow and the area of \u200b\u200bthe company more than 7 thousand. Basic stations: Of these, about 5 thousand. 3G and about 2 thousand. LTE base stations, and recently the number of BS increased by about a thousand.
In just three months in the suburbs, 55% of the total number of new operator base stations in the region were broadcast. At the moment, the company provides high-quality coverage of the territory in which more than 90% of the population of Moscow and the Moscow region live.
By the way, in December, the 3G Tele2 network was recognized as the best in quality among all metropolitan operators.

But I decided to personally check how good the connection is at Tele2, because I acquired a sim card in the nearest shopping center on M.Vakovskaya, with the easiest tariff "very black" for 299 p (400 sms / minutes and 4 GB). By the way, I had a similar Bilaynovsky tariff, which is 100 rubles more expensive.

Checked the speed without leaving away from the box office. Reception - 6.13 Mbps, Transmission - 2.57 Mbps. Considering that I stand in the center of the shopping center is a good result, Tele2's connection well penetrates through the walls of the large shopping center.

On M. Tretyakovskaya. Receiving a signal - 5.82 Mbps, transmission - 3.22 Mbps.

And on M. Krasnogvardeyskaya. Reception - 6.22 MBPS, Transmission - 3.77 Mbps. Measured at the exit from the subway. If we take into account that this is the outskirts of Moscow, it is very decent. I believe that a completely acceptable connection can confidently say that stable, if you consider that Tele2 appeared in Moscow just a couple of months ago.

In the capital, the TELE2 stable connection is, it is good. I really hope that they will come to the area and I can fully enjoy their connection.

Now and you know how the cellular communication works!

If you have a production or service that you want to tell our readers, write to me - Aslan ( [Email Protected] ) And we will make the best report that will see not only the readers of the community, but also the site http://ikasetosdelano.ru

Subscribe also to our groups in facebook, VKontakte, Odnoklassniki and B. google + Pluswhere the most interesting from the community will be laid out, plus materials that are not here and video about how things are arranged in our world.

Jim on the icon and subscribe!

A little sad that the vast majority of people to the question: "How does cellular communication work?", They answer "by air" or at all - "I don't know."

In continuation of this topic, I had one funny conversation with a friend on the topic of mobile communication. This happened exactly a couple of days to celebrated by all communications and telecommists holiday "Radio Day".So it happened that by virtue of his yard of life position, my friend believed that mobile communications works at all without wires via satellite. Exceptionally at the expense of radio waves. At first, I could not convince him. But after a short conversation, everything fell into place.

After this friendly "lecture", the idea appeared to write in a simple language about how the cellular communication works. All as it is.

When you dial a number and start calling, well, or someone calls you, then your mobile phone on the radio channel bindswith one of the antennas of the nearest base station. Where are these basic stations, you ask?

pay attention to industrial buildings, city highways and special tower. They are located large gray rectangular blocks with protruding antennas of different forms. But these antennas are not television and not satellite, but receive transmissioncellular operators. They are directed in different directions to provide subscribers from all sides. After all, we do not know where the signal will come from and where will the "Mount subscriber" bring with a handset? On professional jargon, the antenna is also called "sectors". As a rule, they are installed from one to twelve.

From the antenna, the signal on the cable is transmitted directly to the control unit. Together they form the base station [antennas and control unit]. Several basic stations whose antennas serve a separate territory, for example, the city district or a small town, are connected to a special block - controller. To one controller is usually connected to 15 base stations.

In turn, controllers, which can also be several, are connected to the "Mozgian Center" - switch. The switch provides the output and input of signals to urban telephone lines, on other cellular operators, as well as intercity operators and international relationship.

In small networks, only one switch is used, in larger serving at once more than a million subscribers, two, three or more switches are used, combined again with wires.

Why such complexity? The readers will ask. It would seem that, you can simply connect antennas to the switch and everything will work. And here the base stations, switches, a bunch of cables ... but not everything is so simple.

When a person moves along the street on foot or goes on a car, train, etc. and at the same time talking on the phone, it is important to provide continuity of communication. SUBSCRIBERS PERFORMES mobile networks Called the term "Handover".You must switch the subscriber's phone from one base station on time to another, from one controller to another and so on.

If the base stations were directly connected to the switch, then all these switches would have to manage the switch. And he is "poor" and so there is something to do. Multi-level network diagram makes it possible to evenly distribute the load on the technical means. This reduces the likelihood of equipment failure and, as a result, loss of communication. After all, we are interestedin an uninterrupted connection, right?

So, reaching the switch, our call translates dalee is a network of another mobile operator, urban long-distance and international communication. Of course, this is due to high-speed cable communication channels. Call comes to the switchanother operator. At the same time, the last "knows", on which territory [in the field of action, which controller] is now the necessary subscriber. The switch transmits a telephone call to a specific controller, which contains information, in the area of \u200b\u200bthe base station there is a call destination. The controller sends a signal of this single base station, and in turn "polls", that is, it causes a mobile phone. A tube begins to botherly calling.

All this long and complex process in reality takes 2-3 seconds!

Similarly, telephone calls in different cities of Russia, Europe and the world occur. For communication switzer various operators Communications are used high-speed fiber optic communication channels. Thanks to them hundreds of thousands of kilometers, the telephone overcomes in seconds.

Thanks great Alexander Popov for giving the world Radio! If it were not, perhaps, we would now be deprived of many of the benefits of civilization.

Communication is called mobile if the source of information or its recipient (or both) is moved in space. Radio communication from the moment of occurrence was mobile. Above, in the third chapter it was shown that the first radio stations were intended to communicate with movable ships. After all, one of the first devices of radio communications A.S. Popova was installed on the battleship "Admiral Apraksin". And precisely thanks to radio communication with him, it was possible to save this ship in the winter of 1899-1900 in winter, lured in the ice of the Baltic Sea. However, in those years, this "Mobile Communication" required bulky transceivers for radio communications, which did not contribute to the development of such a necessary individual radio communications even in the armed forces, not to mention private clients.

June 17, 1946 in St. Louis, USA, telephone business leader AT & T and Southwestern Bell launch the first radiotelephone network for private clients. The elemental base of the equipment was the lamp electronic devices, so the equipment was very cumbersome and was intended only for installation in cars. The weight of the equipment without power sources was 40 kg. Despite this, the popularity of mobile communications began to grow rapidly. This created a new, more serious than the massabrytic performance of the problem. An increase in the number of radio resources, with a limited frequency resource, led to strong mutual interference for radio stations operating on the frequency channels, which significantly worsened the quality of communication. To eliminate mutual interference with repeated frequencies, it was necessary to provide a minimum of a hundredkilometer separation in space between two groups of radio systems. That is why mobile communication is based on its own for the needs of special services. For mass implementation, it was necessary to change not only the mass-size indicators, but also the principle of organization of communication itself.

As noted above, in 1947 the transistor performs the functions of electronic lamps, but having significantly smaller sizes. It was the appearance of transistors that had great importance for the further development of radiotelephone communications. Replacing electronic lamps on transistors created the prerequisites for a wide deployment of a mobile phone. The main deterrent was the principle of organization of communication, which would eliminate or at least reduce the influence of mutual interference.

Research of the ultra-thorough-wave range of waves, carried out in the 40s of the last century, made it possible to identify its basic advantage over short waves - wide range, i.e., a large frequency capacity and the main disadvantage-strong absorption of radio waves. The radio waves of this range are not capable of ringering the earth surface, so the range of communication was provided only on the line of sight, and depending on the transmitter power was provided to a maximum of up to 40 km. This flaw soon turned into an advantage that gave an impetus to the active mass introduction of cellular telephony.

In 1947, an employee of the American company Bell Laboratories D. Ring offered a new idea of \u200b\u200borganizing communication. It consisted in dividing the space (territory) into small sections - cells (or cells) by a radius of 1-5 kilometers and in the radio compartment within one cell (by rational repetition of the communication frequencies used) from the connection between the cells. Repeating frequencies significantly reduced the problems of using the frequency resource. This allowed to be used in different hundreds distributed in the space alone and the same frequencies. In the center of each cell was proposed to locate the basic receiving-transmitting radio station, which provided radio communication within the cell with all subscribers. The size of the cells was determined by the maximum range of the radio telephone apparatus with the base station. This maximum range received the name of the cell radius. During the conversation, the cellular radiotelephone is connected to the base station with a radio channel, according to which a telephone conversation is transmitted. Each subscriber must have its own micro-stations - "Mobile Phone" - a combination of a telephone, transceiver and mini-computer. Subscribers are associated with each other through base stations, which are connected to each other and with the public telephony network.

To ensure uninterrupted communication when the subscriber's transition from one zone, it was necessary to use computer control over a telephone signal emitted by the subscriber. It is computer control that has allowed the mobile phone to switch the mobile phone from one intermediate transmitter to another for a thousandth. Everything happens so quickly that the subscriber simply does not notice it. Thus, the central part of the mobile communication system is computers. They find a subscriber who is in any of the cells and connect it to telephone network. When the Subscriber moves from one cell (cells) to another, computers seem to transmit a subscriber from one base station to another and connect the subscriber "someone else's" cellular network to "its" network. This happens at the moment when the subscriber is "a stranger" in the area of \u200b\u200bthe new base station. Thus, they carry out roaming (which in English means "travel" or "vagrancy").

As noted above, the principles of modern mobile communications were the achievement of the late 40s. However, in those days, the computer technique was still at such a level that its commercial use in telephone systems was difficult. Therefore, the practical application of cellular communications has become possible only after the invention of microprocessors and integral semiconductor chips.

The first cell phone apparatus prototype of the modern apparatus designed Martin Cooper (Motorola, USA).

In 1973 in New York, on top of the 50-storey building company Motorola.Under his leadership, the first base station of cellular communication was mounted. She could serve no more than 30 subscribers and connect them with terrestrial link lines.

On April 3, 1973, Martin Cooper scored the number of his boss and said the following words: "Imagine, Joel, that I call you from the world's first cell phone. He is in my hands, and I go on New York street. "

The phone from which Martin called was called Dyna-Tac. Its dimensions were 225 × 125 × 375 mm, and the weight was a little bit of 1.15 kg, which, however, much less than 30 kilogram devices of the end of the fortieth. With the help of the device, you could call and receive a signal, negotiate with the subscriber. On this phone there were 12 keys, of which 10 were digital for a dialing of a subscriber number, and the other two provided the beginning of the conversation and interrupted the call. DYNA-TAC batteries allowed to work in a conversation mode about half an hour, and for their charging required 10 hours.

Despite the fact that the main developments were conducted in the United States, the first commercial network of cellular communications was launched in May 1978 in Bahrain. Two honeycombs with 20 channels in the 400 MHz range served 250 subscribers.

Few later cellular communication began its triumphal march worldwide. More and more countries understood the benefits and amenities that she could bring. However, the absence of a single international standard for using the frequency range, over time, led to the fact that the owner of the cell phone, moving from one state to another, could not use the mobile phone.

In order to eliminate this main drawback from the end of the seventies, Sweden, Finland, Iceland, Denmark and Norway began joint research on the development of a single standard. The result of the research was the NMT-450 communication standard (Nordic Mobile Telephone), which was intended for operation in the range of 450 MHz. This standard first began to be used in 1981 in Saudi Arabia, and only a month later - in Europe. Various NMT-450 options were adopted in Austria, Switzerland, Holland, Belgium, Southeast Asian countries and the Middle East.

In 1983, the AMPS standard network was launched in Chicago (Advanced Mobile Phone Service), which was developed by Bell Laboratories. In 1985, in England, TACS Standard was adopted (Total Access Communications System), which was a type of American AMPS. Two years later, due to the sharply increased number of subscribers, HTACS Standard was adopted (Enhanced Tacs), added new frequencies and partially corrected the flaws of the predecessor. France was stood separately from all and began to use their own standard Radiocom-2000 since 1985.

The following was the standard NMT-900 using frequencies 900 MHz range. A new version It became applied in 1986. It allowed to increase the number of subscribers and improve the stability of the system.

However, all these standards are analog and refer to the first generation of cellular systems. They use an analog method of transmitting information using frequency (FM) or phase (FM) modulation - as in ordinary radio stations. This method has a number of significant drawbacks, the main of which are the possibility of listening to conversations by other subscribers and the impossibility of combating the fading signals when the subscriber movement is moved, as well as under the influence of terrain and buildings landscape. The overload of frequency bands caused interference with conversations. Therefore, by the end of the 1980s, the creation of a second generation of cellular systems based on the database of digital signal processing methods began.

Previously, in 1982, the European Conference of Email and Telecommunication Administrations (CRT) uniting 26 countries decided to establish a special group of Groupe Special Mobile. Its purpose was the development of a single European standard of digital cellular communication. The new communication standard was developed for eight years, and for the first time it was announced only in 1990 - then the specifications of the standard were proposed. The special group initially decided to use the 900 MHz band first, and then, given the prospects for the development of cellular communication in Europe and all over the world, it was decided to allocate for the new standard and the range of 1800 MHz.

The new standard was called GSM - Global System for Mobile Communications. GSM 1800 MHz is also called DCS-1800 (Digital Cellular System 1800). The GSM standard is a digital cellular standard. There is a temporary separation of channels in it (TDMA - multiple access with time division, message encryption, block coding, and GMSK modulation) (GAUSSIAN Minimum Shift Keying).

The first state that launched the GSM network is Finland, which launched in 1992 this is a standard for commercial operation. The following year, the first DCS-1800 One-2-One network earned in the UK. From this point on, the global distribution of the GSM standard worldwide.

The next step after GSM is the CDMA standard that provides faster and reliable communication By using code separation of channels. This standard began to emerge in the United States in 1990. In 1993, CDMA (or IS-95) was applied in the United States in the 800 MHz frequency range. At the same time, the DCS-1800 One-2-One network began in England.

In general, the communication standards were many, and by the middle of the nineties, most of the civilized countries smoothly switched to digital specifications. If the first generation networks allowed to transmit only a voice, then the second generation of cellular systems, which is and GSM, allow you to provide other non-voice services. In addition to the SMS service, the first GSM standard phones allowed to transmit other non-voice data. To do this, the data transmission protocol has been developed, called CSD (Circuit Switched Data - data transmission over switched lines). However, this standard possessed very modest characteristics - the maximum data transfer rate was only 9600 bits per second, and then under the condition of stable communication. However, for the transmission of fax messages such speeds, it was enough.

The rapid development of the Internet in the late 1990s led to the fact that many cellular users wanted to use their tubes as modems, and the existing speeds were clearly not enough for this.
In order to at least somehow, satisfy the need of its customers in accessing the Internet, engineers are inventing the WAP protocol. WAP is a short name from Wireless Application Protocol, which is translated as a wireless access protocol to applications. In principle, WAP can be called a simplified version of the standard Internet protocol of HTTP, only adapted under limited mobile phone resources, such as small display sizes, a small performance of telephone processors and small data transfer rates in mobile networks. However, this protocol did not allow to view standard Internet pages, they must be written in WML, which was adapted for cell phones. As a result, subscribers of cellular networks although they got access to the Internet, but it turned out to be very "trimmed" and little interest. Plus, it was used to access WAP sites that the same channel of communication was used as for the transfer of voice, that is, while you download or view a page, the communication channel is busy, and from the personal account, the same money is written off as during a conversation. As a result, quite an interesting technology was practically buried for some time and was used by subscribers of cellular networks of various operators very rarely.
Manufacturers of cellular equipment urgently had to look for ways to increase the data transfer rate, and as a result, HSCSD technology (High-Speed \u200b\u200bCircuit Switched Data) appeared, which provided quite acceptable speed - up to 43 kilobit per second. At a certain circle of users, this technology has been popular. But still, this technology did not lose the main lack of its predecessor - the data was still transmitted by the voice channel. Developers again had to do painstaking research. The efforts of the engineers were not in vain, and a technology called GPRS (General Packed Radio Services) appeared quite recently - this name can be translated as a data packet data system. This technology uses the principle of separating channels for voice and data transmission. As a result, the subscriber does not pay the duration of the connection, but only the amount of transmitted and received data. In addition, GPRS has another advantage over earlier mobile data transmission technologies - during the GPRS connection, the phone is still capable of receiving calls and SMS messages. At the moment, modern telephone models presented in the market when making a conversation suspend the GPRS connection, which is automatically resumed at the end of the conversation. Such devices are classified as the GPRS terminal of class V. It is planned to produce class A terminals that will allow simultaneously to download data and talk with the interlocutor. There are also special devices that are intended only for data transfer, and they are called GPRS modems or Class C terminals Theoretically GPRS is able to transmit data at a speed of 115 kilobit per second, but at the moment most telecom operators provide communication channel that allows you to develop speed Up to 48 kilobit per second. This is due primarily with the equipment of the operators themselves and as a result, the lack of higher speeds in the market of cell phones.

With the advent of GPRS again remembered the WAP protocol, as now, through new technologyAccess to a small volume of WAP pages becomes many times cheaper than in CSD and HSCSD times. Moreover, many telecom operators for a small monthly subscription fee provide unlimited access to WAP resources of the network.
With the advent of the GPRS, the cellular network has ceased to be called second generation networks - 2G. At the moment we are in the epoch of 2.5G. No voice services are becoming increasingly popular, a cell phone, computer and Internet network occurs. Developers and operators offer us more and more different additional services.
Thus, using the GPRS capabilities, a new message transfer format was created, which was called MMS (Multimedia Messaging Service - Multimedia Messaging Service), which, unlike SMS, allows you to send not only text from a cell phone, but also various multimedia information, for example, Recording, photos and even video clips. Moreover, the MMS message can be transmitted both to another phone that supports this format and on the email box.
Increasing the power of phones processors allows you to download and run on it various programs. To write them, the Java2Me language is most often used. The owners of most modern phones are no longer labor to connect to the Java2ME application site applications and download to your phone, for example, new game or other need program. Also, no one will not surprise the possibility of connecting the phone to a personal computer in order to use special software, most often supplied with the tube, save or edit the address book or organizer on the PC; Being on the road, using a bunch of mobile phone + laptop, get into full-fledged Internet and view your email. However, our needs are constantly growing, the amount of information transmitted is growing almost daily. And more and more requirements are put forward to cell phones, as a result of which the resources of current technologies are not enough to meet our increasing requests.

It is to solve these requests and are intended, the newly created third-generation networks of 3G are sufficiently created, in which data transfer dominates voic services. 3G is not a standard of communication, but the general name of all high-speed cellular networks that will grow and are already growing out of the current existing ones. Huge data transfer rates allow you to transfer high-quality video directly to the phone, implement a permanent connection to the Internet and local networks. The use of new, improved, protection systems allows you to use the phone today to carry out various financial transactions - the mobile phone is completely able to replace the credit card.

It is quite natural that the third generation networks will not become the final stage of the development of cellular communications - as they say, progress is inexorable. It is now passing integration of various types of communication (cellular, satellite, television, etc.), the appearance of hybrid devices, including a cell phone, PDA, a video camera, will definitely lead to the emergence of 4G, 5G networks. And about how this evolutionary development end, today even fiction writers can hardly be able to tell.

At the global level, about 2 billion units of mobile phones are now used, more than two thirds are connected to the GSM standard. The second most popular is CDMA, the remaining of the specific standards used mainly in Asia. Now in developed countries there was a situation of "suggestions" when demand ceases to grow.