Looking at them, I realized that it was time to update the material - the second article was written at a time when Yota was working on Wimax technology, and 4g had just appeared, the first one even earlier.
The new article is not only about modems, but about the mobile Internet in general. It is designed primarily for those who have just begun to understand this topic, that is, “experienced mobile Internet users” are unlikely to find something unknown here.
I want to chew on some of the fundamental subtleties associated with the mobile Internet, "put everything on the shelves", so to speak. Let's start.
What do you need to use mobile internet?
- an agreement (and a SIM card) with a certain mobile operator and a connected tariff (tariff option, package), which implies the presence of a certain amount of traffic or access to the network without restrictions;
- a device that will work with this operator and allow you to directly “surf the Internet”, and (or) make it possible to connect other devices to the network;
- everything should happen in the coverage area of the network of the selected operator.
It seems simple, but in reality - there are enough subtleties, let's sort it out in order.
Where will mobile internet work?
It will work within the coverage area of the network of your chosen operator. At the same time, the better the signal level, the better it will work. The signal level is not the only thing that determines the possible speed.
How will mobile internet work?
There are a number of technologies for transferring data over mobile networks - the speed depends on which technology is used at the moment. Each defined technology must be supported by both the device and the operator base station with which it operates. We also do not forget about the signal level.
The speed will depend on:
- what type of network the operator has in the place where you are;
- what data transfer technologies your device supports;
- what is the signal level in the place where you are (I wrote about it separately).
The speed depends on the current load on the network (primarily relevant for cities) and on the weather (on the contrary, this is especially noticeable outside the city, when the distance to the base station is large).
What types of networks and data transmission technologies exist at the moment?
Second generation networks - 2g (GSM). Includes two data transfer technologies:
GPRS- the slowest option. If we are talking about a smartphone or tablet, then when working with GPRS, the “G” symbol lights up next to the signal strength indicator. The "ceiling" of this technology in ideal conditions is only 171.2 kbps. And conditions are rarely ideal. You can't do much with GPRS - e-mail, surfing (it's better with disabled image loading - otherwise you will wait for loading each page for a very long time), instant messengers. You can safely forget about YouTube, listening to music online and other delights of the modern Internet.
EDGE- already better. When working with this technology, the smartphone or tablet will show the letter "E" next to the signal strength indicator. The theoretical "ceiling" for EDGE is 474 kbps. In real conditions, the speed will, of course, be lower, but still - you can count on 150 - 200 kilobits, and this will already allow you to surf (having angelic patience), play some games (many MMOs do not need a wide channel), and etc., but with multimedia content, as before, it will be hard.
Third generation networks - 3g (WCDMA):
This includes actually 3g (UMTS), and when working in such networks, the smartphone or tablet will show the symbols "3g" near the signal strength indicator. The theoretical maximum data transfer rate is 2048 kbps. This can already be called quite adequate network access speed. You can also talk on Skype and watch videos on YouTube.
HSDPA- a more advanced version. Theoretically possible speed is as much as 84.4 Mbps. In the "field" conditions, I was able to see numbers in the region of 5 - 15 megabits. The smartphone, when working with HSDPA, will show you the symbol "H" or "H +".
Fourth generation networks - 4g (LTE)
And so far, the only technology in this category is actually 4g, or, if you use the “official” rather than marketing name, LTE (although not only LTE. If you are interested, see Wikipedia). In theory, 4g supports speeds up to 173 megabits per second for receiving and 58 for uploading. In practice, I was able to “target” 40 megabit reception (although I often see talk about higher speeds on the net).
About devices
You can use various devices to access the network. It could be:
Modem. Connects to a computer via USB, some tablets also support modem connection - also via USB using an OTG cable (if there is a full-fledged USB port, then without any OTG). Allows you to access the network on the device to which it is connected. If the Internet needs to be distributed, then there are several options. Connect the modem to the router (see the next paragraph). You can distribute from the computer to which the modem is connected, but this requires quite specific settings, especially if you plan to distribute via Wi-Fi. You can, if necessary, distribute via Bluetooth. Theoretically, the tablet to which the modem is connected can also distribute the Internet (additional programs may be required if there is no “portable hotspot” option in the settings).
If the modem was purchased in the salon of one or another operator and carries its identification marks on board, then, with a probability of 99.9%, the modem is "locked", that is, a software restriction is set, due to which the modem only works in the network of its operator. You can overcome this misfortune - the modem can be "unlocked". There is no universal recipe here, so we enter the modem model into Google, add the word “unlock”, and read what we found (most likely it will be all sorts of forums).
Turning not to a communication salon, but to a regular computer store, you can buy a modem that will work with the network of any operator. Keep in mind that it will cost more (maybe even much more) - operators, not infrequently, sell modems, which is called “at a loss” and earn money by selling traffic.
Router + modem. We connect the modem to the router, set up the router - it distributes the Internet - via Wi-Fi, by wire, etc. From the subtle points - the router must have a USB port, in addition, you must first clarify whether a particular router works with a particular modem. You need to look for a list of supported modems on the website of the router manufacturer, where you can also download the latest firmware, which can support new modem models.
Special mobile router. These are sold in communication stores, and are a device that already combines both a modem and a router. Still, not infrequently, there is a battery - so that it can be used in "field" conditions. Like modems, they can be "locked" to one operator. As is the case with modems, in computer stores you can find devices that are not tied to any particular operator.
Cellular telephone. Often, it can also provide Internet access by connecting to a computer or tablet with a wire, or via Bluetooth.
Smartphone or tablet. Most smartphones and tablets (of course, those that support 3g or 4g and have a slot for a SIM card) can act both as a modem, when connected to a computer via wire or Bluetooth, and as a router, distributing the Internet via Wi-Fi. Since we touched on this topic above, I will mention that inexpensive smartphones sold in communication stores under the brands of certain operators are also often “locked”, in two-SIM cards only one SIM card is often “locked”.
Will a 3g modem work in a 4g network and vice versa?
The question is valid not only for modems, but also for any other devices.
Operator networks rarely support just one technology. Often they are supported by everything from 2g to 4g. In the outback there are base stations without 4g, and sometimes without 3g. That is, with rare exceptions (we will consider below), if you see some kind of cell tower, then it is most likely “2g or higher”.
Various devices, most often, also support everything, although it is still quite possible to buy a smartphone or modem in the store that “can” only 2g and 3g.
Other things being equal, there shouldn't be any problems. If you get to a place with a 4g modem (smartphone, tablet) where the operator has 3g coverage, it will simply work in 3g. And even in 2g it will work if you get to a place where there is only such coverage.
If you with a 3g modem (smartphone, tablet) get to a place where the operator has 4g coverage, the device will still work, but again only in 3g. Finally, if you take some old phone that does not even know how to 3g, then it will still work - just in 2g.
There are exceptions to what is described above. For example, the Tele2 network in Moscow and the region is implemented only in 3g and 4g. Or Yota modems - they work only in 4g. And even if you insert a Yota modem SIM-card into a “non-Yota” modem that “can” 3g, nothing will work - that's how everything is arranged with them.
Let's take a closer look at the situation with Tele2 in Moscow: if you insert a Tele2 SIM card into some device that can only work in 2g networks, then nothing will work for you.
A more complicated example - almost all dual SIM devices currently on the market have only one SIM card that can work in 3g \ 4g, while the second one will only work in 2g. This means that when using Tele2 in the Moscow region, you must give the privilege of using 3g \ 4g to this particular SIM card. Under these conditions, you can adequately use the Internet only through Tele2. If you want Internet through a SIM card of another operator, you will have to switch it to 3g \ 4g mode, while the Tele2 SIM will go into the “2g only” mode and simply stop working - I remind you, because Tele2 does not have a 2g network in Moscow.
Smartphones in which both SIM cards can simultaneously work in 3g \ 4g are still few (google and find out if you need one).
About SIM cards and different devices (will a SIM card from a modem work in a smartphone and vice versa)
Looking through the search queries through which visitors come to my site, I often see something like “is it possible to insert a SIM card from a smartphone into a modem” or vice versa “from a modem to a smartphone”. At the time of writing the previous articles, both questions could be answered in the affirmative, but now the situation has changed.
Technically, you can insert a SIM card from a smartphone into a modem without any problems - exactly the same SIM cards are used there and there. Even if you have a micro-SIM in your smartphone, and a full-size SIM in the modem, you can still insert it by simply pressing it against the contacts in the desired position, since the contact pad is the same size there and there. You probably noticed that SIM-cards are now sold universal - initially it is full-sized, and using pre-saddle cuts, it can easily be turned into micro- and nano-SIM. The piece of plastic remaining after this can be used as an adapter. Decided, from a technical point of view, there are no problems.
There are restrictions of a different nature - along with the appearance of tariffs offering unlimited Internet for a smartphone / tablet, there was also a restriction on the part of operators who are not interested in using SIM cards with such tariffs in modems and routers. As a rule, this is stated in the tariff itself - something like "The SIM card is intended for use in a smartphone / tablet, when used in a modem, Internet access will be limited."
There are also modem tariffs, the use of which in smartphones is limited by the operator. And if not limited, then on some of them voice calls are generally impossible, on others high prices are set for “voice”. Be careful!
The final answer to the questions “is it possible to insert a SIM card from a smartphone into a modem” or “A SIM card from a modem into a smartphone” is as follows: depends on your carrier and data plan. If in doubt, call the operator and ask.
About distributing the Internet from a smartphone or tablet
If you have Internet access on your smartphone or tablet, using wire, Wi-Fi or Bluetooth, you can provide network access to other devices - say, a laptop. It is very convenient on the road. This is how I use the Internet at the dacha on weekends, and at home I use the Internet from my smartphone as a “backup channel” - if the wired Internet is turned off, a couple of taps to start the access point on the smartphone - and I'm back online.
That's like all. I hope the article was useful to you 😉
People have long since learned to communicate at a distance. In ancient times, a messenger was sent with news, later letters were written. Now, to say a few words to a distant friend, you can just call him. The main thing is to have a cell phone with you. But how do they connect to each other if they don't even have wires? In this story, I will tell you how the phone works.
What it is?
A mobile phone is more like a walkie-talkie than a regular corded phone. Radio waves are used to transmit the signal.
The difference is that the walkie-talkies are connected to one antenna, and can only be connected by catching a signal from it. Cell phones are not tied to a specific station. While moving, they connect to the antenna from which the strongest signal is received, so we can use communication almost all over the world without changing the SIM card. Antennas, or base stations, have been built all over the world, hiding in billboards, clocks, poles, and even trees. Each of them is responsible for its own zone, which has the shape of a hexagon. In the diagrams, these territories bordering each other resemble a honeycomb. Hence the name - cellular communication.
Who was first?
Who do you think was the first to talk on a cell phone? Of course, it was an employee of Motorola, which released them. In 1973, while on the streets of New York, he called and boasted of a call from an unusual phone at that time to his main competitor. This phone became the prototype of the first mobile phone that hit the stores 10 years later.
For the phone to work, you need to insert a SIM card into it. It contains information about the subscriber, that is, about the person who uses it. The mobile phone starts checking all the frequencies available to it, there are about 160 of them. The six best signals are recorded on the SIM card, these are the signals of your network.
After you have dialed your buddy's number, your phone transmits information about you to the antenna with the strongest signal. Your operator (for example, MTS or Beeline) recognizes you, finds a free channel on which your conversation can take place, and connects you. All this takes only a few seconds.
The conversation itself is a rather complicated technical process. Our voice is broken into segments lasting 20 milliseconds and converted to digital format, then encoded by a special system. Encrypted signals are processed again to remove extraneous noise.
Now cellular telephone serves not only for conversations. One small device fits such simple mechanisms as a simple clock, alarm clock, calculator, calendar, flashlight, as well as complex cameras, Internet access, a player and much more.
While most of us take a landline phone for granted, the phone in your home is one of the most amazing devices ever made. If you want to talk to someone, all you have to do is pick up the phone and dial a few numbers. You can contact this person at any time and chat with him.
The telephone network is spread all over the world, so you can reach almost everyone on the planet. If you remember that only 100 years ago and even less, sending a written message to someone could take several weeks ...
Surprisingly, the phone is one of the simplest devices in your home. The principles of telephone communication have not changed for almost a century. If you have a vintage phone from the 1930s, you can plug it into your phone jack and it will work just fine!
phone internals
The simplest phone consists of three parts:
1. Switch, connecting and disconnecting the phone from the network. This switch is commonly referred to as lever switch. It connects the phone to the network when you pick up the phone.
2. Ddynamic. This is the most common speaker the size of a 50 kopeck coin and a resistance of 8 ohms.
3. Microphone. In the past, telephone microphones were extremely simple and consisted of activated carbon granules sandwiched between two thin metal plates. The sound waves from your voice squeezed and unclenched the beads, changing their resistance and regulating the current flowing through the microphone.
And it will work! You can dial a number on this phone by quickly pressing the lever switch - all telephone switches still recognize " pulse dialing". If you pick up the handset and quickly tap the switch four times, the telephone company switch will know that you have dialed "4".
The only problem with such a phone is that during a call you will hear your voice through the speaker.
Wires and cables
The telephone network starts in your home. P ara copper wires runs from your phone to a thick cable containing many of these copper pairs. Depending on where you are located, this thick cable will go directly into the switchboard of the telephone exchange in your area, or it will be plugged into a box about the size of a refrigerator that acts as digital hub.
Digitization and voice delivery
The hub digitizes your voice at 8,000 times per second and 8-bit resolution. It then collects your voice and dozens of others and sends them all onto a single wire (usually a coax or fiber optic cable) leading to the telephone exchange. Somehow, your line connects to the line disconnect and you can hear a long beep when you pick up the phone.
If you call someone connected to the same station, then the switch simply creates a closed circuit between your phone and the phone of the person you dialed. If it's a long distance call, then your voice is digitized and combined with millions of other voices. Your voice usually travels over a fiber optic line to the receiving party's telephone exchange, but it may also be transmitted by satellite or communication towers.
Creation of own telephone network
Not only the phone is a simple device. Communication between you and the telephone exchange is even easier. In fact, you can easily create your own telephone network using two telephones, a 9-volt battery, and a 300-ohm resistor you can buy from the radio market. You can assemble all this equipment in the following way: one wire connects both phones directly, and the second wire connecting the phones has a power supply and a resistor connected in series. If both people pick up the handsets at the same time, they will be able to talk to each other normally at a distance of several kilometers.
The only thing your little intercom won't be able to do is call another phone to ask the person on the other end to pick up the phone. The bell signal is supplied with 90 volts alternating current at a frequency of 20 hertz.
The connection to the telephone exchange consists of two copper wires. One of them transmits 6 to 12 volts DC, approximately 30 mA. The microphone modulates the sound waves, the speaker at the other end reproduces this modulated signal. That's all.
If you go back to the days of the manual switch, it is easy to understand how a large telephone network once worked. In those days, there were many pairs of copper wires running from every house to the telephone exchange in the city center. The switchboard operator sat in front of a large billboard with one slot for each subscriber. Above each connector was a small light bulb. A large battery was connected through a resistor for each wire pair. When someone picked up the receiver on their phone, the toggle switch closed the circuit and sent current through the wires between the house and the telephone exchange. This turned on the light bulb above this socket on the switchboard. The operator would connect their headset to this jack and ask who the person would like to talk to. The operator would then send a ring tone to the receiving party and wait for someone there to pick up the phone. After the handset was picked up, the operator connected the two people together, just like a simple intercom. It's very simple!
Tone dialing
In modern system phones, operators have been replaced by electronic switch. When you pick up the handset, the switch senses the closing of the circuit and plays a long beep sound. This way you know the switch and your phone are working. The sound of a long beep is a combination of a 350 Hertz tone and a 440 Hertz tone. The set of digits of the number is also accompanied by sounds of different tonality. If the number is busy, you hear an intermittent busy tone, which is made up of a 480 Hertz and 620 Hertz tone.
Bandwidth
In order to ensure longer distance calls, transmitted frequencies are limited bandwidth about 3000 hertz. All frequencies in your voice below 400 Hertz and above 3400 Hertz are excluded. From this, the voice on the long-distance telephone has a characteristic sound.
Therefore, it is better not to arrange musical performances on the phone, so as not to become the hero of a joke:
Petka and Vasily Ivanovich meet. Vasily Ivanovich says: “What do people find in these Beatles?! They sing in monotone! Petka asks: “Vasily Ivanovich, where did you listen to the Beatles ?!” Vasily Ivanovich: “Like where? Yesterday Furmanov sang a couple of their things to me on the phone ... "
Cellular communications have recently become so firmly established in our daily lives that it is difficult to imagine modern society without it. Like many other great inventions, the mobile phone has greatly influenced our lives, and many of its areas. It's hard to say what the future would be like if it wasn't for this convenient form of communication. Definitely the same as in the movie "Back to the Future 2", where there are flying cars, hoverboards, and more, but no cellular service!
But today in a special report for will be a story not about the future, but about how modern cellular communications are arranged and work.
In order to learn about the operation of modern cellular communication in the 3G / 4G format, I invited myself to visit the new federal operator Tele2 and spent the whole day with their engineers, who explained to me all the intricacies of data transmission through our mobile phones.
But first, let me tell you a little about the history of the emergence of cellular communications.
The principles of wireless communication were tested almost 70 years ago - the first public mobile radiotelephone appeared in 1946 in St. Louis, USA. In the Soviet Union, a prototype mobile radiotelephone was created in 1957, then scientists from other countries created similar devices with different characteristics, and only in the 70s of the last century in America were determined the modern principles of cellular communication, after which its development began.
Martin Cooper - inventor of the Motorola DynaTAC portable cell phone prototype weighing 1.15 kg and measuring 22.5x12.5x3.75 cm
If in Western countries, by the mid-90s of the last century, cellular communications were widespread and used by a large part of the population, then in Russia it only began to appear, and became available to everyone just over 10 years ago.
Bulky brick-shaped mobile phones that worked in the formats of the first and second generations have gone down in history, giving way to smartphones with 3G and 4G, better voice communication and high speed Internet.
Why is it called cellular? Because the territory on which communication is provided is divided into separate cells or cells, in the center of which there are base stations (BS). In each "cell" the subscriber receives the same set of services within certain territorial boundaries. This means that when moving from one "cell" to another, the subscriber does not feel territorial attachment and can freely use communication services.
It is very important that there is continuity of the connection when moving. This is ensured by the so-called handover, in which the connection established by the subscriber is as if picked up by neighboring cells in a relay race, and the subscriber continues to talk or dig in social networks.
The entire network is divided into two subsystems: the base station subsystem and the switching subsystem. Schematically, it looks like this:
In the middle of the "cell", as mentioned above, is the base station, which usually serves three "cells". The radio signal from the base station is radiated through 3 sector antennas, each of which is directed to its own "cell". It happens that several antennas of one base station are directed to one "cell" at once. This is due to the fact that the cellular network operates in several bands (900 and 1800 MHz). In addition, this base station may have equipment of several generations of communication (2G and 3G) at once.
But only the third and fourth generation equipment, 3G / 4G, is installed on the Tele2 BS towers, as the company decided to abandon the old formats in favor of new ones, which help to avoid interruptions in voice communications and provide a more stable Internet. Regulars of social networks will support me that in our time the speed of the Internet is very important, 100-200 kb / s is no longer enough, as it was a couple of years ago.
The most common location for a BS is a tower or mast built specifically for it. Surely you could see the red and white BS towers somewhere far from residential buildings (in a field, on a hill), or where there are no tall buildings nearby. Like this one, which is visible from my window.
However, in urban areas it is difficult to find a place for a massive structure. Therefore, in large cities, base stations are placed on buildings. Each station picks up a signal from mobile phones at a distance of up to 35 km.
These are antennas, the BS equipment itself is located in the attic, or in a container on the roof, which is a pair of iron cabinets.
Some base stations are located where you would not even guess. Like on the roof of this parking lot.
The BS antenna consists of several sectors, each of which receives / sends a signal in its own direction. If the vertical antenna communicates with phones, then the round one connects the BS to the controller.
Depending on the characteristics, each sector can serve up to 72 calls at the same time. A BS can consist of 6 sectors and serve up to 432 calls, but usually fewer transmitters and sectors are installed at stations. Cellular operators, such as Tele2, prefer to install more BS to improve the quality of communication. As I was told, the most modern equipment is used here: Ericsson base stations, transport network - Alcatel Lucent.
From the subsystem of base stations, the signal is transmitted towards the switching subsystem, where the connection is established with the direction desired by the subscriber. The switching subsystem has a number of databases that store information about subscribers. In addition, this subsystem is responsible for security. To put it simply, the switch is It has the same functions as the female operators, who used to connect you with the subscriber by hand, only now it all happens automatically.
The equipment for this base station is hidden in this iron cabinet.
In addition to conventional towers, there are also mobile variants of base stations placed on trucks. They are very convenient to use during natural disasters or in crowded places (football stadiums, central squares) during holidays, concerts and various events. But, unfortunately, due to problems in the legislation, they have not yet found wide application.
In order to provide optimal radio signal coverage at ground level, base stations are designed in a special way, therefore, despite the range of 35 km. the signal does not extend to the flight altitude of aircraft. However, some airlines have already begun installing small base stations on their aircraft to provide cellular communications inside the aircraft. Such a BS is connected to the terrestrial cellular network using a satellite channel. The system is complemented by a control panel that allows the crew to turn the system on and off, as well as certain types of services, such as turning off the voice on night flights.
I also looked into the Tele2 office to see how specialists control the quality of cellular communications. If a few years ago such a room would have been hung to the ceiling with monitors showing network data (congestion, network failures, etc.), then over time, the need for such a number of monitors has disappeared.
Technology has evolved over time, and such a small room with a few specialists is enough to monitor the operation of the entire network in Moscow.
A few views from the Tele2 office.
At a meeting of company employees, plans are being discussed to capture the capital) From the beginning of construction to the present day, Tele2 has managed to cover all of Moscow with its network, and is gradually conquering the Moscow region, launching more than 100 base stations weekly. Since I now live in the area, it is very important to me. so that this network comes to my town as soon as possible.
The company plans for 2016 to provide high-speed communications in the metro at all stations, at the beginning of 2016 Tele2 communications are present at 11 stations: 3G / 4G communications at the Borisovo, Delovoy Tsentr, Kotelniki, Lermontovsky Prospekt metro stations , Troparevo, Shipilovskaya, Zyablikovo, 3G: Belorusskaya (Koltsevaya), Spartak, Pyatnitskoye Highway, Zhulebino.
As I said above, Tele2 abandoned the GSM format in favor of third and fourth generation standards - 3G / 4G. This allows you to install 3G / 4G base stations with a higher frequency (for example, inside the Moscow Ring Road, BS stand at a distance of about 500 meters from each other) in order to provide more stable communication and high speed mobile Internet, which was not the case in networks of previous formats.
From the company's office, I, in the company of engineers Nikifor and Vladimir, go to one of the points where they need to measure the communication speed. Nikifor stands in front of one of the masts, on which the equipment for communication is installed. If you look closely, you will notice a little further to the left one more such mast, with the equipment of other cellular operators.
Oddly enough, but cellular operators often allow their competitors to use their tower structures to place antennas (of course, on mutually beneficial terms). This is because building a tower or mast is expensive, and such an exchange saves a lot of money!
While we were measuring the speed of communication, passers-by grandmothers and uncles asked Nikifor several times if he was a spy)) "Yes, we are jamming Radio Liberty!").
The equipment actually looks unusual, you can assume anything from its appearance.
The company's specialists have a lot of work, given that in Moscow and the region the company has more than 7 thousand employees. base stations: about 5 thousand of them. 3G and about 2 thousand. LTE base stations, and recently the number of BS has increased by about a thousand more.
In just three months, 55% of the total number of new base stations of the operator in the region were put on the air in the Moscow region. Currently, the company provides high-quality coverage of the territory where more than 90% of the population of Moscow and the Moscow region lives.
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 Tele2's connection is, so I bought a SIM card at the nearest shopping center on Voikovskaya metro station, with the simplest "Very Black" tariff for 299 r (400 sms/minutes and 4 GB). By the way, I had a similar Beeline tariff, which is 100 rubles more expensive.
I checked the speed without moving far from the cash register. Reception - 6.13 Mbps, transmission - 2.57 Mbps. Considering that I am standing in the center of a shopping center, this is a good result, Tele2 communication penetrates well through the walls of a large shopping center.
At metro station Tretyakovskaya. Signal reception - 5.82 Mbps, transmission - 3.22 Mbps.
And on m. Krasnogvardeiskaya. Reception - 6.22 Mbps, transmission - 3.77 Mbps. Measured at the exit of the subway. If we take into account that this is the outskirts of Moscow, it's very decent. I think that the connection is quite acceptable, we can confidently say that it is stable, given that Tele2 appeared in Moscow just a couple of months ago.
There is a stable Tele2 connection in the capital, which is good. I really hope that they will quickly come to the region and I will be able to fully use their connection.
Now you know how cellular communication works!
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A huge number of BS - base stations have been installed on the territory of Russia. Probably, many of you have seen red and white structures towering in the fields or structures installed on the roofs of non-residential buildings. Each such base station is capable of picking up a signal from a cell phone at a distance of up to 35 km, communicating with it via service or voice channels.
After you dialed the number of the desired subscriber on your phone, the following happens: the mobile phone finds the nearest BS, contacts it via the service channel and requests a voice channel. After that, the BS sends a request to the controller (BSC), which then goes to the communicator. If the called party is served by the same operator as you, the communicator will check the Home Location Register (HLR) database to find out exactly where the person you are calling is located and redirect the call to the correct switchboard, which will then transfer the call to the controller and then to the Base Station. And finally, the Base Station will contact the mobile phone of the right person and connect you with him. And if the one you want to talk to is a subscriber of another cellular operator, or you call a landline number, then the switch will “find” the corresponding switch of another network and turn to it. Sounds pretty confusing, right? Let's try to analyze this issue in more detail.
But back to the equipment. As we have already said, from the BS the call is transferred to the controller (BSC). Outwardly, it is not much different from the Base Station:
The number of base stations that are able to serve the controller can reach six dozen. The controller and the BS communicate via optical or radio relay channels. The controller controls the operation of the radio channels.
Below you can see what a switch is:
The number of controllers serviced by the switch varies from two to thirty. The switches are placed in large rooms filled with metal cabinets with equipment.
The task of the switch is to manage traffic. If earlier, in order to talk to each other, subscribers had to first contact the telephone operator, who then manually rearranged the necessary wires, now the switch does an excellent job with her role.
Inside the cars there are devices designed for data collection and processing:
Controllers and switches are under vigilant control 24 hours a day. Tracking is carried out in the so-called CKC (Air Control Center of the Network Control Center).
