Cellular base station antenna. Cellular stations. How dangerous is radiation from a cell tower

Recently, the media reported that the residents of Brest were not allowed to build a communications tower in the courtyard of houses on Graevka. They collected more than a hundred signatures, and were also on duty near the building materials to prevent the construction of the base station. Reason - "The tower can have a negative impact on both the health of the children in school and the residents of nearby houses"... Some believe that the residents are doing the right thing, while others call it "the fight against windmills." Are the towers dangerous cellular in fact? What harm can they do next to a residential building and how much do they emit?

Base station cellular operator near a house in Brest (microdistrict "Kovalevo")

Two towers are installed near my house on Kovalevka mobile communications... One has been in operation for several years, the other was installed quite recently. It’s good that it’s not right under the windows. Personally, such a neighborhood would have bothered me, regardless of how the station emits. Every time, looking out the window, “face to face” I would not like to meet a metal contraption (even if it is disabled).
A break in the Internet for more than a dozen articles, I realized that there was no consensus on this matter. So to be afraid or not of radiation? For myself, I singled out one article, more or less lucidly telling about the principle of operation of a base station of a mobile operator in Russia. Not claiming to be the ultimate truth, but it will be useful for readers to familiarize themselves with it. Especially if you are worried about this question.
So.
Company blog VimpelCom (Beeline)

It often happens that as soon as a cellular antenna is installed on the roof of a residential building, complaints from residents immediately begin. There are standard ones like "My head started to hurt!"

Obviously, a new thing is to blame for everything. In a number of cases, due to such complaints, it does not reach the direct inclusion of the base station, and the antennas installed, but not yet put into operation, have to be removed and moved.

Below I will tell how the base station emits and I will attach the calculations.

What's dangerous

The danger of radio waves for the human body was studied in this moment not to the end, but research is being carried out, you can read about them, for example, here in the section "How does EMF affect health." In general, if we analyze the research, it becomes clear that yes it is dangerous!

What is being done to avoid this danger? In our country, there is a standard according to which, in particular, the construction of base stations is carried out. In SaNPiN 2.1.8 / 2.2.4 it is written that the maximum permissible energy flux density for the frequencies at which our BSs operate (900, 1800, 2100 MHz) is 10 μW / cm2, or 0.1 W / m2. It is from this number that we will continue to build on in the assessment.

In fairness, it should be said that in many Western countries such norms allow the local population to be irradiated with an energy flux density a couple of orders of magnitude higher, approximately 1 mW / cm2, that is, 10 W / m2.

Assessment of real exposure

So, we have a number, above which it is impossible to jump in any case. How can you understand whether the radiation in your particular apartment / office will be higher or lower than this value?
First, what is this energy flux density? This is how much the radiated antenna energy will pass through a certain area (cm2 in SaNPiNe). If the antenna radiated in all directions equally, then all the energy would be smeared over the sphere around the antenna. Well, such antennas are not particularly needed by the cellular operator, we most often use directional sector panel antennas that radiate in a certain direction (directional patterns can be found in the manufacturers' catalogs, for example, here).

Here is a typical radiation pattern:

Horizontal (left) and vertical radiation patterns on a logarithmic scale.

Horizontal (left) and vertical radiation patterns at normal linear scales.

Well, the energy flux density itself can be calculated if you look into any book on radio engineering.

And now with examples

First of all, the simplest option is to put the antenna on the house opposite, what will happen if it looks directly at you, unprotected by anything (even a foil hat)?

For conventional antennas, the gain in the main lobe of the radiation pattern is, for example, 18dBi (this is 63 times). At the antenna input, suppose, from the BS goes as much as 40 W (this is rarely used, usually not higher than 20 W, but for an estimate it can be exaggerated).

Then the energy flux density with distance will fall as in the picture:

Here in blue - restrictions on SaNPiN. It turns out that at a distance of 45 meters from the antenna you can already be at least around the clock and, according to sanitary standards, it will be absolutely harmless to our health.

Let's take a more real case, when the BS is installed on the opposite house, but there is a window glass on the way between you and the antenna (the signal is attenuated in it by 4dB, that is, 2.5 times). We will even concretize, I will take my example - a house across the street, on which the BS is located, according to Google earth between him and my windows 110 meters. In this case, we get that dinner, I get 0.0066 mW / m2. This 15 times less than the limit level - you can safely eat without hiding behind the refrigerator!

More often it happens that you and the antenna are separated not by glass, but by a wall. In reinforced concrete walls, the signal attenuates even more, most often it is about 15dB (almost 32 times).

We saw what would happen if the antenna was pointed directly at you, that is, they were specifically aiming at your apartment / office.

Even more often you are not in the main lobe of the radiation pattern, where the radiation is maximum, but somewhere on the side, where the antenna gain is already noticeably lower than 18dBi. In these cases, naturally, the radiation will be even lower, for example:

A fairly common situation is illustrated here when the antenna shines above the subscriber, and he is served by the lower lobes of the radiation pattern. In the direction shown, the antenna gain is 24dB (250 times) lower than the main lobe level.

Well, now let's return to our example from the very beginning: what if the antenna was installed on the roof of your house?

Then the antenna gain in the direction of the apartment on the upper floor will be approximately -5dBi (attenuation by 3 times), the ceiling will give attenuation by 15dB (32 times). If we count, we get that cats that have stopped giving birth and dying cockroaches at a distance of 2 meters from the antenna receive 0.0078 W / m2, that is, a little more than me, having dinner at 110 meters from the antenna.

What does this mean, cap?

If the base station is over your head on the roof, almost nothing gets to you. On the other hand, if you decide to climb on the roof and turn the sector antenna towards you, and then sunbathe under it, you will be in for a very unpleasant surprise.

Note to the paranoid

Do not cuddle with the base station turned on. At least for a long time - for sure.
Do not keep the femtocell on your lap or on your desktop. The guaranteed safe distance from it to you is 1 meter on either side.
It is categorically not worth getting into the focus of the radar at various military facilities: the power there is several times higher.
Radiation from a BS on a neighboring house is several times less dangerous for health in comparison with the periodic radiation of a Chinese microwave (where it hits from all the cracks). Factors comparable in power to the radiation of a BS directly on the roof above you are common home wifi and bluetooth headsets.

About our employees

As for our employees, during routine work, when they come directly to the antennas and can already get tangible harm, it is customary for us to turn off the BS for the duration of work.

conclusions

From the above, it can be understood that almost any feasible option for installing base station antennas is harmless to humans (according to SaNPiN). If you remember that 40 W of power is very rarely supplied to the antenna, then the soul becomes even easier. Plus, it's worth remembering the norms in most Western countries, where the dangerous level starts much higher.

P.S. The website of the mobile operator MTS in Belarus even has a whole section dedicated to health. Here are some answers from the category "Mobile communications and health: truth and fiction":

- If the base station is installed on the roof of the house where I live (work), how dangerous is it for my health?
In this case, you are in a "blind spot" - ie. the radiation from the antennas does not affect you at all. it spreads to the sides, and the antennas practically do not radiate vertically down or up. In general, even in the most "dangerous" zone - that is, when located with the BS approximately at the same level horizontally - the danger zone is no more than 30 meters. Radiation tends to fade in proportion to the square of the distance (if the distance from the radiation source has increased by 2 times, the radiation has been attenuated by 4 times, etc.). Thus, a few tens of meters from the base station is almost a 100% guarantee that there will be no radiation that can affect health.

- What, according to experts, can have a greater effect on human health - a base station or itself cellular telephone?
The answer of experts is unambiguous: the phone itself! The fact is that we usually press the phone to our ear when talking, it is as close to the body as possible. The base station, however, is always at least a few tens of meters away, which practically eliminates the effect of radiation from it. The cell phone emits a certain electromagnetic radiation at the time of establishing a connection with the nearest BS (several such attempts are made per minute). At the moments when the base station is removed or there is no base station nearby, the phone sends a signal of maximum power.

- What are the EMR standards in force in the Republic of Belarus and what normative document regulates them?
According to the Sanitary Norms and Rules of the Republic of Belarus (SanPiN) 2.2.4 / 2.1.8.9-36-2002 "Electromagnetic radiation of radio frequency range (EMR RF)", the maximum permissible level of surface power flux density in the frequency range in which the equipment of cellular operators operates is 10 μW / cm2 (10 microwatts per square centimeter).

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125 comments to “Cellular tower near the house. Should you be afraid? "

1. Dima:
It can be concluded that the inhabitants of the Graev house were right - they will indeed be irradiated ...
But what is interesting is that at the same time, people want a quality connection.
2.admin:
Is not a fact. It is necessary to look at the distance from the tower to the house. Besides, it is not known which will turn out better in the end. The base station is installed for a reason. So the connection is not very good there. As a result, when dialing and talking, the phone will "radiate" more strongly, sending and holding a stronger signal to the nearest tower. Roughly speaking, having got rid of the cell tower, the inhabitants of Hrayevka will more "irradiate" their heads when talking on their mobile phones.
3. Dima:
admin, the antenna would be 15-20 meters from the house, according to residents. The question, of course, is where she would be sent. But I am sure that no one would direct them towards the windows of the house.
Inhabitant Raisa Ivanovna generally suggested setting up towers outside the city ... No comment at this point.
So, completely ignorant of the theory, the tenants themselves make themselves worse ...
4.admin:
If the tower "looked" at me directly through the window, I would also sign against the construction. Even if they put it at a safe distance of 50 meters. It is a psychological discomfort to constantly observe a cell tower and wires in the window.
5.gelaz:
I wonder if the residents - those from Graevka - have a microwave oven at home? Not, better tv from the fraternal republic of Poland, with a diagonal of 42 "" at a distance of 3-4 meters from the face every evening for 2-4 hours? Let them calculate how they are irradiated there ... This is not to mention the pernicious influence of the content being viewed.
But in general, yes, it is better to have all BS outside the city in the exclusion zone. Kilometers over 200 is desirable. It must be done on the first of April. Cut off the connection and say that, according to the demands of the residents, all base stations were urgently removed outside the residential zones in view of the fact that they emit such an infection. 0.0068-0.001 μW / sq. Cm. That will be funny. Mgm.
6. Anonymous:
We live in the private sector and we have a tower placed 3 meters from the house, right behind the wall. I don’t know what to do and where to complain.
7.admin:
Anonymous If you think that in your house / area the radiation from the cell tower exceeds the norm, I think you can contact the Brest Regional Center for Hygiene, Epidemiology and Public Health. There you can find the department of radiological research. There is even a price list on the site.
You do the measurement. If everything is okay, sleep well. If there is an excess, it is already the road to the city executive committee. Naturally, with the documents of the examination.
8.b4w:
In the photo there are 30-40 meters. That is, when the window is open, the norms will be exceeded.
9.admin:
b4w, it is possible and will be if the antenna is directed strictly towards the windows. I didn't measure the distance. But after all, the tower is not installed just by poking a finger on the map. Some measurements are taken, after all, they receive a sanitary passport before being put into operation.
In general, the installation still largely depends on the tenants. The main thing is not to just panic and not demand to take out all the base stations. mobile operators out of town. If the tower does not look out of the window, sleep well.
10. Gennadievich:
admin writes:
b4w, it is possible and will be if the antenna is directed strictly towards the windows. .................. If the tower does not look out of the window, sleep well.

"... sleep well ..." dear comrade ... Doesn't it seem to you that THIS, something reminds ... = -O
11.admin:
Gennadievich, what? * UNKNOWN *
12. Dmitry:
In all such situations, it is necessary to install composite communication antennas directly in front of the house of the management of cellular companies, then this will be an indicator of safety, and rightly so.
13.admin:
Dmitriy, I am in favor with both hands. Only it is unlikely that something will change from this ... ((
14. Svetlana:
15.Anton:
The radiation levels from the towers are significantly less than from the cell phones themselves in our hands, said John Bitell, Emeritus Research Fellow at the University of Oxford's Pediatric Oncology Research Group. at the same time, the honorary of honorary John Bitell forgets that the cell tower works around the clock with thousands of phones at the same time, which means that the radiation level from the towers, in principle, cannot be much less than from the cell phones themselves.
oh, those regalia and false orders.
there is only one standard - 250-300 meters from any living creature (and no directions of the antenna of the tower to people), otherwise - write to the prosecutor's office right away. other authorities only waste other people's forces and put everything on the brakes. which has already been verified.
after an application to the prosecutor's office - for some reason everyone begins to do their job, and to become familiar with the content of "SanPiN 2.1.8-2.2.4.1383-03 Hygienic requirements for the placement and operation of transmitting radio technical objects", to investigate installation projects and take measurements. under other circumstances, everyone is happily silent.
even an unbiased person can submit an application to the prosecutor's office about the improper installation of the tower.
in addition, the article implies a permissible power of 25 watts and a maximum dangerous range of 45-50 meters. - it is right. but there is one point.
when installing several towers in one place, the total radiation becomes dangerous at a greater distance, and the power of 25 watts from three towers will give 74 watts at 120 meters in the frequency coincidence region. I hope you haven't forgotten that this type of connection is called CELLULAR. I wonder why there is not a word about this in the article?
so don’t worry, but apply. competent people will take other competent people, come, check and draw a conclusion.
16.admin:
anton, do not go to extremes and run to write a statement.
Firstly, if you have any suspicion, no one bothers you to go to the department of radiological research in your city (we have it in the Center for Hygiene, Epidemiology and Public Health) and take a measurement for a small fee. Then compare with the acceptable standards.
Secondly, with regards to the fact Why does a person receive more "radiation" during a conversation than being, say, 100 meters away from her on the street? Radiation flux density directed from a point source decreases in inverse proportion to the square of the distance to the source.
Let us take as a source of "radiation" a cell tower a hundred meters away and a telephone near the ear, and calculate the distance to the brain. With the same outgoing "radiation" power, the energy flux density from the phone near the ear will be 10 thousand times higher!
17. Olga:
Good day! We live on the top floor, we didn’t worry about it. But now it is necessary to change living conditions and an apartment is offered, which is adjacent to the attic of the neighboring lower section (a split-level house), that is, it turns out that a cell tower may not be installed behind the wall now, but at any time.
Now we are thinking about this question.
Should I settle for such an apartment? What is the harm?
18. Gleb:
Recently, a tower was installed right in the yard ... (Moscow)
The phone was already good, but now this thing stands right in the middle of the playground (Yu.Butovo) - around 4 houses, just all the radiations are looking in 4 directions. to houses 15-20 meters, and since the tower is located on a building 5 meters high and is directed slightly upward, then all the emitters look straight into the windows ... i.e. more than signal to go nowhere, except to rest against a 16-storey skyscraper and reflect back ... from an engineering point of view, absolutely complete idiocy.
even if, according to its indicators, this tower fits into some standards, it is not correct to place it in places where people and children gather ... And in general - I personally do not want to see this ugliness in my yard. let them put it on a 200-meter mast, near the track somewhere ... their range of action is several kilometers - why the heck put it at a 5-meter height in a closed yard ??
Che, I scored before, but now I’m definitely going to the housing office, and then I’ll write to the prosecutor’s office ... if they don’t sweat, I’ll ask the local thugs to cut it down at night to f ** k.
19. squirrel:
It is not true that the antennas do not emit downward yet, and how on the ATB near the house they installed several pieces inside the store, the head starts to hurt, then all day long how do people work there?
20. Svyatoslav:
Theory differs from practice, and this is confirmed by time.
Several years ago, a cell tower with a height of about 25 meters was installed on the territory of the hospital. A couple of years passed and poplars and fruit trees died within a radius of 100 meters. Three years ago, a cell phone was installed on the roof of a neighboring building. Acacia grew up to the 4th floor near the house - it turned yellow and withered. In the same house on the 5th floor, it is not possible to measure the voltage in the network - the numbers on the tester run by themselves, and the switchman reacts to touching one of the probes with his hand, moreover, at any limits. Interference even on computer speakers- you can't listen to music. The residents of the house have complaints such as intense hair loss, headaches, a sharp deterioration in vision, nervous disorders, thyroid disease. All this is done by the microwave - the same radiation. The cell phone also fry the brain, especially if it is far from the cell phone. By the way, I have noticed more than once that my cat reacts to the phone a couple of seconds before the call. So it's safer to talk through a headset or speakerphone.
21. Igor:
Svyatoslav, the headset connected to a cell phone starts to function as an external antenna of this phone. The intensity of the electromagnetic field at its end (respectively, in headphones stuck in the ears) is maximum. Accordingly, talking through a headset cannot be attributed to a safe alternative to putting the phone to your ear. But speakerphone is one of the options, yes, but who wants to make their conversations public domain ... =)
22. Michael:
Headsets are different. If a connector with a wire through which only sound is connected to the phone, then such a headset is not dangerous. Because the phone is at a safe distance from the head. For example, in a pants pocket or even in a bag.
23. Igor:
Michael, thanks for the comment. Then the question is - why do you think the radio does not play in cell phones without connecting headphones? Answer: the wavelength of FM radio stations is 10 times longer than the wavelength of the GSM band, therefore the built-in telephone antenna (whose own resonance is somewhere in the range of 0.9 - 1.8 GHz) catches these stations extremely unsatisfactorily (remember - optimal antenna length should be ¼ wavelength). Thus, by connecting a headset to receive sound through headphones, a person, in fact, simultaneously connects and external antenna, which, although not intended for the cellular range, still performs the functions of an antenna.
24. Michael:
Igor, there is no dispute here that the wire with the headphones is additionally and an antenna for receiving FM radio. And the fact that this wire is also an additional antenna for the built-in antenna of the phone itself - here I don't know what to tell you. This can only be proven by knowing for sure that it is so. What is the point for a manufacturer to release a phone and talk about safe "hands-free" knowing that when connecting ordinary headphones to the phone, the normalized exposure indicators electromagnetic radiation on the brain will be overestimated?
25. Igor:
Okay. Apparently, to clarify / refute this, as they often write in scientific documents, "in-depth research is needed" =) If I find any, I will post the information here
26. Anonymous:
27. We must fight for our rights! :
Down with those creepy electromagnetic wave emitters!
A person has the right to health and safety!
Where are they looking law enforcement?
28. Anonymous:
who knows the formula by which the calculation is made
29. Vasily:
I also asked this question, towers next to the house, about 150 meters. I even bought a device, finances allowed, indeed the EMR in the apartment is 0.1-0.2 μW / cm2, and when measured near the head with a telephone up to 100 μV / cm2 and pulsates strongly, and measured in a room that is generally deaf in communication (towers far), so at the moment the connection gave out about 500 μW / cm2, wow. Beware of your phone, which is always near !!! at least keep some distance from your ear.
30. Michael:
Basil, thanks, valuable information. Yes, the cell phone emits. Nobody pays special attention to this now. Although the waves are and will be emitted. This is the paradox. Maybe even cell towers are not as harmful as the phone itself during a call. No one knows yet what can destroy the tower or the telephone itself. Time will tell. But then it may be too late. American scientists are already keeping statistics on this problem and the results are not yet encouraging. In general, the less you talk on your mobile phone, the better. Average talk time per day is 2-2.5 hours.
31. Vasily:
I read somewhere, if all the waves on the earth (radio, amy) were colored, we would not see the sky. A person is already adapted to high-frequency EMR up to 1 μW / cm2. One thing somehow calms down, cellular communication has been for more than 20 years and almost everyone in the last 10 years has been using telephones, there is no general disease, of course, long-term consequences cannot be ruled out, but we are also not going to live forever, so that in 100 years what then the consequences.
Of course, if the effect of amy on a person is not yet 100% proven, it is better to take care, especially for children when using mobile phones. By the way, when measuring the emi from the radiotelephone in the office, around the base with the phone within a radius of 1.5-2 meters, the emi is 0.15 μW / cm2, and the handset, when called, generally gives not feeble readings more than a cell phone, although its base is practically nearby.
32. Eugene:
I would like the cell towers in front of the windows to be in an aesthetically pleasing form, for example, in the form of a giant plant.
33. Hope:
oh-eh, I read it here, hair on end%). And I got to YOU in search of information about the dangers of a cell tower. They began to install it 10 meters from our house. I appeal to you, as to the strong half of humanity, advise what to do, where to start? Or wait until the construction is completed, and then take measurements (so, it's a pity the company will suffer losses)? Thanks in advance: -D
34. Vasily:
Hope The company will definitely not suffer losses, they are shabby in this business, I think the tower in front of you will be higher than the roof and, accordingly, you will not get into the danger zone.
35. Anonymous:
Evgeniy, this is an additional waste of money. The question is at whose expense and how?
36. Michael:
Hope, I agree with Vasily. First you need to prove that the antenna you are installing is harmful. Until it is installed, it will be difficult to prove it. It's nothing you can do. The experience of court cases on this issue is very small. Now this is the business of Internet operators, which they do directly for us (and we ourselves ask for this, coming to their offices and concluding an agreement with them to connect a cell phone with support for a 3G signal, and now 4G, as well as to connect digital television). Operators are forced to increase the signal coverage area because of ourselves, calculating where the signal is weaker there and setting up a tower. What would you like? There is only one way out - everyone should give up high-quality cellular communications and digital television. Ignore the program of the regional government to switch from analogue to digital broadcasting. I have to disappoint you Nadezhda. There is only one way out - to move to live in the forest.
37. Vasily:
It is interesting when these towers disappear, all the same, progress is going by leaps and bounds, is it really impossible to come up with something else for receiving and transmitting a signal: aesthetic, unobtrusive, with less electromagnetic radiation
38. farit:
I am an engineer, I have to supply power to these towers, so everywhere they say from the beginning cockroaches disappeared, then the bees died, and then the elderly began to die from mainly cancer, where is the truth?
39. Michael:
Perhaps about cockroaches and bees. Does not work on ants. It's hard to say about cancer.
40. Vasily:
I am inclined to trust all the same WHO than OBS (one grandmother said). Here is a link to the WHO response from September 2013 on BS and cell phones. www.who.int/features/qa/30/ru/
41. leisan:
In our village we have put a cell tower right in the yard where children run around school kindergarten residential buildings this is right because of this cancer. Where can I turn to
42. Vasily:
I would advise you to contact the Sanitary and Epidemiological Service to measure the level of electromagnetic radiation, if this does not help, then to a psychiatrist, there will be much more problems from the head. For that matter, have you ever wondered what all children eat, every day and what is contained in GMO products (as if not on the topic of the forum, but still), radiation envelops us everywhere, with different wavelengths and intensities. And yet, at this point, I would check the radiation at an industrial frequency of 50 Hz, which our electric wires, WHO recommendation rate 0.2 μT (Russia 10 μT SanPiN 2.1.2.1002-00)
43. Anonymous:
laysan, please re-read the article again, it tells everything. Over time, cell towers will be everywhere. And including where you don't want to the most. Progress is unlikely to be challenged. If you succeed, it will not last long. Progress will take its toll.
44. Michael:
Basil"Radiation at an industrial frequency of 50 Hz, which our electrical wires emit" I understand that this is about shielding wires? If so, then it is unlikely to save. Most likely it is better to re-ground (PE - conductor) of the electrical installation. There will be more benefits from this.
45. Vasily:
Michael, Quite right, but in order to do something, you need to make sure of this, and even in the sanitary and epidemiological supervision it is recommended to keep all sockets in the house with grounding, for safety and to reduce EMP from wires. In general, in terms of radiation, I consider the most dangerous is electromagnetic radiation from power lines, the wavelength of which is simply huge, which penetrates a person through, then meter waves from radio transmitters go, but cellular communication is centimeter waves are perceived only by human skin 1/40 wavelength and only when high dose and prolonged exposure causing heat.
46. Alina:
Those. eyes suffer the most?
47.Ekaterina:
We installed a tower in bunk 10, saying this is an Internet tower almost next to the house, about 100 meters away. Please tell me what harm it brings to health and can these towers be installed next to residential buildings?
48. Vasily:
I am constantly amazed at how the risks associated with the use of mobile communications are perceived. If a person voluntarily uses a mobile phone, then he perceives this risk of getting sick as low, although the level of radio frequency fields from a mobile phone is much higher, and if we cannot influence the construction of new base stations, then we perceive the risk from this "misfortune" to be high. And more often than not, a great benefit or benefit forces a person to significantly increase the risks.
49. Abylai:
Good day to all!
I wanted to ask how dangerous it would be for the residents of the house if such an antenna was installed on the roof of a two-story building. Antenna for 4G Internet.
50. Vasily:
Abylai, The question is not correct, how many antennas will there be and maybe only 4G? The house does not fall under the electromagnetic flow, but the press has data that the apartments located under the antennas also have EMP, within the normal range, figures from 0.7 to 2.4 μW / cm2 are given, as if the radiation from the antenna falls in the form icicles.
51. Irina:
Please tell me where to complain if you installed antennas?!?!?!?!?!
52. Vasily:
In Rospotrebnadzor, if you are in Russia, they have hygiene centers in each subject, as they are called, they can send a representative for money to you to measure the density of the electromagnetic flux, but 1 in 100, that you will have an excess of 10 μW / cm2
53. Andrew:
Irina, die. It will be more pleasant for everyone. The stupid-headed people were already getting fed up with their complaints.
54. Molokovka:
Michael, ... in your pants pocket, your cell phone will irradiate your prostate ...;)
55. Molokovka:
Andrey, ... judging by your inadequate reaction to Irina, your head is definitely dull! ;))))))))))))))))) Check if there is a tower in close proximity to your home ... maybe the dullness came from it ?! ;)
56. Vasily:
In Sweden and Japan, the number of cellular antennas is 1 km2 more than in the rest of the world, only there, and for some reason, life expectancy is longer, you may need to lead a healthy lifestyle without looking at cellular antennas!
57. Michael:
Molokovka, you guessed wrong. I don't carry my phone in my pants pocket. And if you can call it a telephone. And if you want to sarcastically, then you are not on this forum.
58. Michael:
Basil, an interesting opinion. I believe that cell towers affect life expectancy, but so that it would be possible to completely agree with this, this is definitely not. Here you need to conduct research, keep statistics on many parameters. This takes time. In general, this is a separate topic.
59. Vasily:
Michael, Research on high-frequency radiation goes for more than 50 years, especially in the last 20 years after the advent of cellular communications. The WHO at the UN has already invested hundreds of millions of dollars in this research, do you, Mikhail, think that this is a worldwide conspiracy?
An interesting fact in Sweden mobile radio remote control 100 μW / cm2 (recommended by WHO), Russia 10 μW / cm2. The remote control for an industrial frequency of 50 Hz in Sweden is 0.2 μT (recommended by WHO), and Russia is 10 μT.
60. Ivan:
It seems to me that the problem is not in the power of the station, but directly in the presence of HF radiation, which can enter into resonance with the natural frequencies of the body and disrupt its work. In this case, the proximity to the station is not critical, the presence of this EM pollution is important, to which the body does not know how to react
61. Michael:
Basil, this is hardly a worldwide conspiracy. But people will not invent just like that, at least the majority. Where there is a 100% guarantee that base stations are installed with all applicable rules and regulations. Who checks it? And if they do, then their right not to tell the truth is also theirs. Sweden is one of many countries that has achieved economic growth and prosperity in many areas for a long time. Russia is still on the way to this. It is better to dispense with comparisons. These are two different civilizations.
62. Vasily:
Michael In emotional people, the psychosomatic factor works for five plus, no matter how much you prove them otherwise. Why don't they then throw away their cell phones, these are the links of the same system? Exposure to radio frequency (RF) fields emitted from mobile phones is typically more than 1000 times that of base station emitted fields.
63. Michael:
Basil, I find it difficult to answer your statement.
64. Vasily:
Michael, information about 1000 times taken from the WHO website
and I have a device for measuring EMP from 50 MHz to 3.5 GHz, just cellular communication, the maximum value of 450-500 μW / cm2 from the phone was recorded in the back of the building at the time of receiving a call, and the average value from the BS in the room was 0.25 μW / cm2.
65. Victoria:
A cell tower is being installed near our house, it is at least 20 meters away from us. It is unhealthy because nuclear signals are sent directly to us, but they put this tower on a children's playground. What to do?
66. Anonymous:
When you are irradiated, the connection is no longer necessary * CRAZY *
67. If:
If the tower were harmless, then it would be erected even near the State Duma, the tax administration, and they are standing near our simple houses, here is the answer: -!
68. Vasily:
If You no longer know what to think of in order to justify your ignorance, there is no other way to name it. Take Victoria to your company with her "reactor on the tower".
I would understand if you had a phobia and you would not use your phone, so no message was written here and you are talking on it, without even delving into what kind of EMP comes from it.
69. Alex:
The remoteness of the TV tower. The 22-storey building under construction is separated from the TV tower by two 14-storey buildings and 1100 meters. the windows do not overlook the side of the TV tower.
The question is - is the safe distance from home to the TV tower?
Where can I find the radiation pattern
70. Nina Alexandrovna:
Thank you for giving such a well-grounded (with simple calculations) answer. YOU are a great fellow.
71. Alexander:
a tire service was built at my bobushka next door. right behind the fence they put a mts tower and animals constantly walk in the garden (geese.utki.indyuki.by.kury) what do you think will harm them ??? :(
72. Vasily:
Alexander why aren't you worried about your grandmother's health in the first place?
How good it is for the animals that they do not know what a cell tower is, otherwise, out of excitement, the bull producer stopped doing his job, and the chickens left the grandmother without eggs: -D
73. Michael:
Basil, you are Joker! =) I'm thinking here that if a 4G connection has appeared, then 5G is probably not far off, and so on. This means that the data transfer rate will increase and, therefore, the basic power of the transmitters will need to be increased. How much it will be "harmful" time will tell. In the meantime, I believe that cellular communication is still more harmful than all these towers. A cell phone is, in fact, the same receiver-transmitter as a tower, only a phone in your pocket, and another transmitter-receiver (tower) is raised to n-height. I think why do many people have new and new questions about all these towers, radiation? Because, the Creator did not create life next to the electromagnetic field. That is not created and that's it! And we live. We live in spite of everything, as invented by technical progress. And while we live, more and more new questions will be asked. I am not suggesting anything, it’s true, thinking out loud.
74. Vasily:
Michael As far as I know, the electrical power of transmitters has only decreased with the advent of 4G communications.
At the expense of cell phones, most people do not have a principle of understanding how it works, and even more so, if everyone around uses a cell phone, the risk of using it in the understanding of an individual is reduced
Initially, there were not only electromagnetic fields, but also GMOs, harmful emissions into the atmosphere, and what was not, nothing, a person lives and adapts
75. Niko:
may not be harmful, but the cost of an apartment after the appearance of such a tower under the window is noticeably reduced.
76. Researcher:
Bad article. "Regular home Wi-Fi" - this is turned down. Everyone knows that Wi-Fi is VERY harmful. And the last thing is cellular communication, it is NOT radio waves. As long as possible.
77. admin:
Researcher, you mean to say that all of us are being deceived and the phones work in the other frequency range?
78. Researcher:
Here, in principle, there is nothing to lead round dances. Everything has long been explained by scientists: UNDER the tower, you can only receive the reflected signal. This means that there is no big danger under the tower. It's another matter when some idiots sleep and put their cell phone on the floor at the head of the bed, i.e. receive a DIRECT signal because the "emitter" is BELOW. Here is radiation, be healthy, forgive the carom.
But you better tell me this. So you write here "installed an MTS tower", "installed a Beeline tower ... So, it turns out that new and new towers will be installed for each operator? Or is it still possible to hang the same radiation on one tower? Or the more operators on the tower, the more they radiate? That's what I'm interested in.
79. Researcher:
admin writes:
Researcher, are you saying that all of us are being deceived and the phones operate in a different frequency range?

Nobody is cheating. Cells are of course in a different range, read any instructions.
80. Sapiens:
Hello. worked at Ericsson as an engineer 4 years ago. A former colleague, now an operator's network optimizer, comes to me with a proposal to install a BS-audor on my section of a private house. In principle, I do not mind, but there is one condition for installing the tower on my part. One tower, 15-20m, costs decent money. I am interested in business and, as it were, I do not see any harm in this, since the radio and antennas will be high. Communication in the area is really bad. Now they are looking for a candidate with a tower. I’m wondering, shouldn’t the operator install the tower himself?
81. Titmouse:
I have been working in mobile communications for about 5 years. But not in Moscow, but in Alma-Ata.
The standard power of base stations is 47 dbm, which corresponds to 50 W (standard power in the city), and 51dbm - 120 W (This power was not included in the city, only outside the city). So in Almaty it was forbidden to install base station antennas on residential buildings. And in Moscow, the chaos is complete. By the way, Vasiltsovsky camp 5.2, there are generally suicide bombers on the top floors. Aerial directly above the skylight. It is generally not clear how the antennas were installed there without the consent of the residents.
And it is difficult to give advice to your case. A measurer is called and measures the field strength in your apartment. If it gets into the data on the table, then you are in luck. From my own experience, I’ll say that at work we had a base station that was designed to work indoors, so 30 minutes of being around ended up with headaches. Cellular antennas are all directional and concentrate power in a specific direction. If the antenna is not directed strictly at you, then, in principle, it's okay. But it is not recommended to stay closer than 5 meters for a long time near the switched on antenna, wherever it looks.
82. Vova Putin:
Researcher,
> Bad article. "Regular home Wi-Fi" - this is turned down. Everyone knows that Wi-Fi is VERY harmful.
Yes? And what then? Someone died from him or what? Radio has existed for almost 1.5 centuries and so far it has not harmed anyone, well, of course, if you stick your head in a microwave oven ... And so, radio transmitters of the same power that are used in the cellular network, and even more so in a wafer, do not significantly affect health. For almost 150 years of the use of radio by mankind, "in small doses" it did not harm anyone.
> And the last thing is cellular communication, it is NOT radio waves. As long as possible.
And what is it then, excuse me?
83. Serik:
Titmouse, I live in Almaty (Ryskulov Akhrimenko district). There is a Tele2 tower across the house from me (turned in my direction). Everything is fine, but after installing it, I had problems with the Internet ... very strong interference. I began to catch the Altel modem badly. There are also problems with wifi, a neighbor is connected to my wifi, and his Internet is constantly lost. We changed modems, adapters, installed a repeater ... checked the equipment in my office ... everything works.
In general ... is it legal to set up a watchtower among the private sector? It's just that I'm not the only one who has problems, and we are thinking about a class action lawsuit.
84. Andrew:
Recently I began to notice (listen) that my actions. down to the details, they are discussing from the house opposite. There is a hotel in this house, on the roof of which there are antennas, like a cell tower. As I understand, they have almost a video image (mine).
Guys, help (who is dedicated), reluctance to see a doctor. Could this be and how to hide (without moving)?
85. Michael:
Andrey, apparently you can't do without a doctor
86. Tamara:
At the cell tower. Megaphone and Beeline connection is on a 9-storey building. My son and I are 12 years old and my mother live on the 9th floor. It turns out that 5 meters from her. I am very worried about their health! I filed a complaint with Rospotrebnadzor, but they told me that there was no harm to the body. But I do not believe! If I'm right help me please. Find the truth!
87. Tamara:
You do not live in Tobolsk by any chance ??? I live in a hotel where there is a tower! Andrey,
88. Vasily:
Tamara, I do not think that you can win here and the towers will be removed if Rospotrebnadzor gave you such a conclusion. If this worries you so much, I advise you to contact an independent examination, now there are enough of them everywhere so that they can measure EMP, the service will be paid. But in practice of measurements, I do not think that the radiation standard will be exceeded, and the figure will be several times lower.
89. Vasily:
Tamara, during long-term measurements of EMP in the Central Federal District, the following values were revealed in the premises of buildings on the roofs of which towers are installed, the average value is 0.89 μW / cm2, the maximum is 5.21 μW / cm2, with a standard of 10 μW / cm2.
90. Anonymous:

aslan wrote in February 2nd, 2016

Cellular communication has recently become so firmly established in our daily life that it is difficult to imagine modern society without it. Like many other great inventions, the mobile phone has greatly influenced our life, and in many of its areas. It is difficult to say what the future would be like if it were not for this convenient form of communication. Probably the same as in the movie "Back to the Future-2", where there are flying cars, hoverboards, and much more, but no cellular connection!

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

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

But first, I'll tell you a little about the history of the emergence of cellular communications.

The principles of wireless communication were tried out almost 70 years ago - the first public mobile radiotelephone appeared in 1946 in St. Louis, USA. In the Soviet Union, a prototype of a 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 the modern principles of cellular communication were determined, after which its development began.

Martin Cooper - inventor of the portable cell prototype Motorola phone DynaTAC weighing 1.15 kg and dimensions 22.5x12.5x3.75 cm

If in Western countries, by the mid-90s of the last century, cellular communication was widespread and used by most of the population, then in Russia it only began to appear, and became available to everyone a little over 10 years ago.

Bulky brick-like mobile phones that worked in the first and second generation formats have gone down in history, giving way to smartphones with 3G and 4G, better voice communication and high Internet speed.

Why is the connection called cellular? Because the territory in which communication is provided is divided into individual cells or cells in the center of which base stations (BS) are located. In each "cell" the subscriber receives the same set of services within certain territorial boundaries. This means that 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 provided thanks to the so-called handover, in which the connection established by the subscriber is, as it were, picked up by neighboring cells on the relay, and the subscriber continues to talk or dig in social networks.

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

In the middle of the "cell", as mentioned above, is the base station, which typically serves three "cells". The radio signal from the base station is emitted through 3 sector antennas, each of which is directed to its own "cell". It so 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 on the BS Tele2 towers there is only equipment of the third and fourth generation - 3G / 4G, since the company decided to abandon old formats in favor of new ones, which help to avoid interruptions in voice communication and provide a more stable Internet. Regulars of social networks will support me in the fact that nowadays Internet speed is very important, 100-200 kb / s is no longer enough, as it was a couple of years ago.

The most common location for the BS is a tower or mast built specifically for it. Surely you could see the red and white towers of the BS somewhere far from residential buildings (in a field, on a hill), or where there are no tall buildings nearby. Like this one that 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 located on buildings. Each station picks up the 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 wouldn't 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 telephones, then the round antenna connects the BS to the controller.

Depending on the characteristics, each sector can handle up to 72 calls simultaneously. The BS can consist of 6 sectors and serve up to 432 calls, however, usually fewer transmitters and sectors are installed at the stations. Cellular operators, such as Tele2, prefer to install more base stations 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 base station subsystem, 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 performs It has the same functions as the female operators who used to connect you with the subscriber by hand, only now all this happens automatically.

The equipment for this base station is hidden in this iron cabinet.

In addition to conventional towers, there are also mobile versions 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.

To ensure optimal radio coverage at ground level, base stations are designed in a special way, therefore, despite the range of 35 km. the signal does not apply to the flight altitude of the aircraft. However, some airlines have already begun to install small base stations on their aircraft that provide cellular communications inside the aircraft. Such a BS connects to a terrestrial cellular network using 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 communication. If a few years ago such a room would have been hung up 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.

Technologies have developed greatly over time, and such a small room with several specialists is enough to monitor the operation of the entire network in Moscow.

Few views from the Tele2 office.

At a meeting of the company's employees, plans are being discussed to capture the capital) From the beginning of construction until today, Tele2 has managed to cover the whole 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 region, it is very important to me. so that this network comes to my town as quickly as possible.

The company plans for 2016 to provide high-speed communication in the metro at all stations, at the beginning of 2016 Tele2 communication is present at 11 stations: 3G / 4G communication at the Borisovo metro, Delovoy Tsentr, Kotelniki, Lermontovsky Prospekt , Troparevo, Shipilovskaya, Zyablikovo, 3G: Belorusskaya (Koltsevaya), Spartak, Pyatnitskoe shosse, Zhulebino.

As I said above, Tele2 abandoned the GSM format in favor of the third and fourth generation standards - 3G / 4G. This makes it possible to install 3G / 4G base stations with a higher frequency (for example, inside the Moscow Ring Road, BSs 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 in the 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 opposite one of the masts on which communications equipment is installed. If you look closely, you will notice another such mast a little further on the left, with equipment from other cellular operators.

Oddly enough, but cellular operators often allow their competitors to use their tower structures to accommodate antennas (of course, on mutually beneficial terms). This is because building a tower or mast is expensive and can save you a lot of money!

While we were measuring the speed of communication, Nikifor several times passers-by grandmothers and uncles asked if he was a spy)) "Yes, we are jamming Radio Liberty!).

The equipment actually looks unusual, from its appearance you can assume anything.

The company's specialists have a lot of work, considering that in Moscow and the region the company has more than 7 thousand. base stations: of which about 5 thousand. 3G and about 2 thousand. base stations LTE, 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. At the moment, the company provides high-quality coverage of the territory where 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 the capital's operators.

But I decided to personally check how good Tele2's connection is, so I bought a SIM card in the nearest shopping center on Voykovskaya metro station, with the simplest "Very black" tariff for 299 rubles (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 on the spot. 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 Tretyakovskaya. Signal reception - 5.82 Mbps, transmission - 3.22 Mbps.

And at the Krasnogvardeyskaya metro station. Reception - 6.22 Mbps, transmission - 3.77 Mbps. I measured it at the exit from the subway. If you take into account that this is the outskirts of Moscow, it is very decent. I believe that the connection is quite acceptable, we can confidently say that it is stable, considering that Tele2 appeared in Moscow just a couple of months ago.

Tele2 has a stable connection in the capital, which is good. I really hope that they will come to the region as soon as possible and I will be able to take full advantage of their connection.

Now you know how cellular communication works!

If you have a production or service that you want to tell our readers about, write to me - Aslan ( [email protected] ) and we will make the best report that will be seen not only by the readers of the community, but also by the site http://ikaketosdelano.ru

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Plan:

1. Building cellular communications.

2. The structure of cellular communications.

3. The history of the development of cellular communications.

Cellular communications are the most modern and rapidly developing area of telecommunications. It is called cellular because the territory in which communication is provided is divided into separate cells or cells.

As a rule, in each cell the subscriber receives the same set of services and within certain territorial boundaries receives these services at the same price. Thus, moving from one cell to another, the subscriber does not feel territorial attachment and can freely use communication services. The continuity of the connection is also important.

While moving the connection established by the subscriber (voice call, packet data transmission) should not be interrupted. This is due to the so-called handover(Handover). The connection established by the subscriber is, as it were, seized by the neighboring cells on the relay, and the subscriber continues, unwittingly, to talk or travel through the vastness of the Internet.

So, let's look at what the cellular network consists of. The entire network is divided into two subsystems: a base station subsystem and a switching subsystem.

The main elements of the base station subsystem (as it is not difficult to guess) are the base stations themselves ( Bts). They just create those honeycombs, which were mentioned at the beginning. Each base station typically 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. Sometimes you can find a situation when 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). In addition, this base station may have equipment of several generations of communication at once ( 2G and 3G).

The most common location for a base station is a tower or mast built specifically for it. However, in urban areas it is difficult to find a place for a massive structure. Therefore, in large cities, base stations are located on buildings. In addition, mobile versions of base stations located on trucks have recently appeared. They are very convenient to use during natural disasters or in places of mass gatherings of people (football stadiums, central squares) during holidays, concerts, football matches. But, unfortunately, due to problems in the legislation, they have not yet found wide application.

Base station on the tower

Base station on the roof of the building

Mobile base station

Oddly enough, but cellular operators often allow their competitors to use their tower structures to accommodate antennas (Naturally, on mutually beneficial terms). This is due to the fact that building a tower or a mast is an expensive pleasure, and such an exchange allows you to save a lot of money!

We have covered the basic elements of a cellular network. Here, the terms of the standard were specifically applied. Gsm... However, both in the previous and in the subsequent standards there are similar elements and functions, only under different names.

Radio communication is organized not only with the help of fixed radio communication networks, but also with the use of networks with mobile objects (SRPO).

A radio communication network with mobile objects is a set of technical means with which it is possible to provide mobile objects with communication between themselves and with subscribers telephone network... It is designed to serve subscribers during international, national and regional movements (roaming) and allows communication between subscribers when they cross the borders of different geographic zones.

Radio communication networks with mobile objects are classified according to several criteria (Fig. 3.8). Technological SRPOs belong to certain departments and services (gas industry, railway transport, ambulance, fire protection, etc.). They are intended to provide radio communication services to a limited number of individuals and legal entities.

Classification of radio communication networks with mobile objects

Technological SRPOs are subdivided into dispatching, trunking and radio data transmission networks. Dispatching SRPOs are intended for radiotelephone communication of officials of control bodies with subordinate mobile objects, as well as subscribers among themselves.

Cellular SRPO refers to public terrestrial radio communication networks with mobile objects, which provide subscribers with all types of services of conventional telephone connection... They are built in the form of a set of networks covering the served territory, in which frequency reuse is used to ensure the efficient use of the allocated frequency resource and high network capacity.

Trunking (radial and radial-zone) networks are designed to provide communication services mainly to subscribers of departmental networks based on the implementation of multiple access to a small number of radio channels with limited or no access to the public telephone network. Trunking networks allow replacing radio communication networks with a fixed frequency distribution and integrating various user groups within the same communication network in order to increase the efficiency of using the radio frequency spectrum.

From a topological point of view, a cellular network is built in the form of a collection of cells, or cells, covering the served area. The general structure of a cellular radio communication network with mobile objects is shown in Fig. 3.9.

The structure of the cellular radio network

The cellular network structure is based on the principle of frequency reuse - the main principle of the cellular network. In addition, the elements of the cellular network are:

- switching center;

- base stations;

- mobile stations, or subscriber radiotelephones.

A cellular base station (BS) serves all mobile stations within its cell, while the base station provides a resource for establishing connections upon request of mobile subscribers, usually on an equal footing.

When a subscriber moves from one cell to another, his service is transferred from one base station to another. All base stations of the network, in turn, are closed to the switching center, from which there is an access to the unified telecommunication network of the Russian Federation.

Currently, the pan-European standard GSM-900 is widely used. In this standard, mobile station transmitters operate in the 890-915 MHz frequency range, base station transmitters in the 935-960 MHz range. There is a constant separation of 45 MHz between the transmit and receive bands. Each of the sub-bands is divided into 124 frequency channels with a step of 200 kHz. The maximum communication range is 35 km.

The GSM standard provides a high degree of security for transmitted messages due to their encryption using an encryption algorithm with a public key. The functional interfacing of the system elements is carried out by a number of interfaces.

In the technology of building trunking communication, the principle is used in which a specific channel is assigned for each communication session individually, depending on the distribution of the load in the system, and the load traffic is mainly closed within the networks. Subscribers' access to the public telephone network (PSTN) is limited.

Currently, radial and radial-zone trunking networks are used. Such a network includes:

- a base station, consisting of an antenna-feeder device, transceiver modules, controllers for each transceiver module and a base controller;

- zone equipment (station), consisting of autonomous repeaters, connecting lines with a public network and controllers;

- control equipment, consisting of a system terminal "system manager", dispatcher consoles.

In trunking networks built on a radial principle, the entire channel resource is assigned to one central base station (CDS). The antenna of such a station is located at the highest point of the proposed service Fig. 3.10. An example of such an architecture is the Soviet Antey radio communication network, created in 1960.

Radial Trunking Network Structure

The considered scheme has a number of disadvantages, in particular, to expand the coverage area, it is necessary to increase the power of the subscriber station (SS), which accordingly increases the overall level of interference.

With a small number of subscribers, an increase in the service area can be achieved using the radial-zone principle. A so-called single-cell network with several antenna placement points and broadcasting on a common wave is being formed. In this case, along with the main antenna placement point (UKS), there is a number of auxiliary points (ZKS) connected by communication lines with the main one (Fig. 3.11).

The structure of a trunking network built on a radial-zone principle

In general, the technology for building trunking networks provides for the following:

- use of the method of free selection of an unoccupied radio access channel from the channel bundle allocated in each service area. This is achieved by creating a common service (signaling) channel for all users in each zone, through which call signals are received to the corresponding base station, including the identification of the called subscriber, as well as the number of the calling subscriber;

- they do not provide continuous communication when subscribers cross the borders of the radio coverage zones of base stations. "Handover" is replaced by the operation of re-entering the network when the communication quality deteriorates due to the transition of the user from one zone to another;

- endowing base stations with the functions of local control of cells by directly connecting subscribers who are in the support area through a local switch, as well as connecting mobile users to a local automatic telephone exchange (ATS), which has direct outputs to a local switch of a base station or through a dispatch center.

And again, some general educational material. This time we will focus on base stations. Let us consider various technical aspects of their placement, design and range, as well as look inside the antenna unit itself.

Base stations. General information

This is how cellular antennas installed on the roofs of buildings look like. These antennas are an element of a base station (BS), specifically, a device for receiving and transmitting a radio signal from one subscriber to another, and then through an amplifier to a base station controller and other devices. Being the most visible part of the BS, they are installed on antenna masts, roofs of residential and industrial buildings, and even chimneys. Today you can find more exotic versions of their installation, in Russia they are already installed on lighting poles, and in Egypt they are even "disguised" as palm trees.

The base station can be connected to the operator's network via radio relay communication, therefore, next to the "rectangular" antennas of the BS units, you can see a radio relay dish:

With the transition to more modern standards of the fourth and fifth generations, to meet their requirements, stations will need to be connected exclusively via fiber optics. In modern BS designs, optical fiber becomes an integral medium for transmitting information even between nodes and blocks of the BS itself. For example, the figure below shows the design of a modern base station, where fiber optic cable is used to transfer data from the RRU (Remote Controlled Units) antenna to the base station itself (shown by the orange line).

The base station equipment is located in non-residential areas of the building, or is installed in specialized containers (fixed on walls or poles), because modern equipment is quite compact and can easily fit into system unit server computer. Often the radio module is installed next to the antenna unit, this allows you to reduce losses and dissipation of the power transmitted to the antenna. This is how the three installed radio modules of the Flexi Multiradio base station equipment look, fixed directly to the mast:

Base station service area

To begin with, it should be noted that there are different types base stations: macro, micro, pico and femtocells. Let's start small. And, in short, the femtocell is not a base station. It is rather an Access Point. This equipment is initially aimed at home or office users and the owner of such equipment is a private or legal entity. a person not related to the operator. The main difference between such equipment is that it has a fully automatic configuration, starting from the assessment of radio parameters and ending with the connection to the operator's network. Femtocell has the dimensions of a home router:

Picocell is a low-power base station owned by the operator and using IP / Ethernet as a transport network. Usually installed in places of possible local concentration of users. The device is comparable in size to a small laptop:

Microcell is an approximate implementation of a base station in a compact form, very common in operators' networks. It differs from the "big" base station by the reduced capacity of those supported by the subscriber and lower emitting power. The mass, as a rule, is up to 50 kg and the radius of the radio coverage is up to 5 km. Such a solution is used where high capacities and network capacities are not needed, or where it is not possible to install a large station:

And finally, a macrocell is a standard base station on the basis of which mobile networks... It is characterized by powers of the order of 50 W and a coverage radius of up to 100 km (in the limit). The rack weight can be up to 300 kg.

The coverage area of each BS depends on the height of the antenna section, the terrain and the number of obstacles on the way to the subscriber. When installing a base station, the coverage radius is far from always brought to the fore. As the subscriber base grows, the maximum bandwidth of the BS may not be enough, in this case the message "network busy" appears on the phone screen. Then the operator over time in this area can deliberately reduce the range of the base station and install several additional stations in places of greatest load.

When you need to increase the network capacity and reduce the load on individual base stations, then microcells come to the rescue. In a megalopolis, the radio coverage area of one microcell can be only 500 meters.

In urban conditions, oddly enough, there are places where the operator needs to locally connect a section with large quantity traffic (areas of metro stations, large central streets, etc.). In this case, low-power microcells and picocells are used, the antenna units of which can be located on low buildings and on street lighting poles. When the question of organizing high-quality radio coverage inside closed buildings (shopping and business centers, hypermarkets, etc.) arises, then pico-cell base stations come to the rescue.

Outside cities, the range of operation of individual base stations comes to the fore, so the installation of each base station at a distance from the city is becoming an increasingly expensive enterprise due to the need to build power lines, roads and towers in difficult climatic and technological conditions. To increase the coverage area, it is advisable to install the BS on higher masts, use directional sector emitters, and more low frequencies less attenuated.

So, for example, in the 1800 MHz range, the BS operating range does not exceed 6-7 kilometers, and in the case of using the 900 MHz range, the coverage area can reach 32 kilometers, all other things being equal.

Base station antennas. Let's take a look inside

In cellular communications, sector panel antennas are most often used, which have a radiation pattern of 120, 90, 60 and 30 degrees. Accordingly, to organize communication in all directions (from 0 to 360), 3 (DN width of 120 degrees) or 6 (DN width of 60 degrees) antenna units may be required. An example of organizing a uniform coverage in all directions is shown in the figure below:

And below is a view of typical radiation patterns on a logarithmic scale.

Most base station antennas are broadband, allowing operation in one, two or three frequency bands. Starting with UMTS networks, unlike GSM, base station antennas are able to change the radio coverage area depending on the network load. One of the most effective methods of radiated power control is to control the tilt angle of the antenna, in this way the irradiated area of the radiation pattern is changed.

Antennas can have a fixed angle of inclination, or they can be remotely adjusted using a special software located in the BS control unit, and built-in phase shifters. There are also solutions that allow you to change the service area from the general data network control system. Thus, the coverage area of the entire sector of the base station can be adjusted.

Base station antennas use both mechanical and electrical control of the pattern. Mechanical control is easier to implement, but often leads to distortion of the shape of the radiation pattern due to the influence of structural parts. Most BS antennas have an electrical tilt angle adjustment system.

The modern antenna unit is a group of radiating elements of the antenna array. The distance between the array elements is chosen in such a way as to obtain the smallest level of side lobes of the radiation pattern. The most common lengths panel antennas 0.7 to 2.6 meters (for multi-band antenna panels). The gain ranges from 12 to 20 dBi.

The figure below (left) shows the design of one of the most common (but outdated) antenna panels.

Here, the radiators of the antenna panel are half-wave symmetrical electric vibrators above the conductive screen, located at an angle of 45 degrees. This design allows you to form a diagram with a main lobe width of 65 or 90 degrees. In this design, two- and even three-band antenna units are produced (albeit rather large-sized). For example, a tri-band antenna panel of this design (900, 1800, 2100 MHz) differs from a single-band one, about twice the size and weight, which, of course, makes it difficult to maintain.

An alternative technology for the manufacture of such antennas involves the implementation of strip antenna emitters (square-shaped metal plates), in the figure above on the right.

And here is another option, when half-wave slot magnetic vibrators are used as the emitter. The power line, slots and screen are made on one printed circuit board with double-sided foil glass fiber laminate:

Taking into account the modern realities of the development of wireless technologies, base stations must support the operation of 2G, 3G and LTE networks... And if the control units of base stations of networks of different generations can be accommodated in one wiring closet without increasing the overall size, then significant difficulties arise with the antenna part.

For example, in multiband antenna panels, the number of coaxial trunks reaches 100 meters! Such a significant length of the cable and the number of soldered joints inevitably leads to losses in the lines and a decrease in the gain:

In order to reduce electrical losses and reduce soldering points, microstrip lines are often made, this makes it possible to perform dipoles and a power supply system for the entire antenna using a single printed technology. This technology easy to manufacture and provides high repeatability of antenna characteristics during its serial production.

Multiband antennas

With the development of communication networks of the third and fourth generation modernization of the antenna part of both base stations and cell phones is required. Antennas are required to operate in new additional bands in excess of 2.2 GHz. Moreover, work in two and even three bands must be done simultaneously. As a result, the antenna part includes rather complex electromechanical circuits, which must ensure proper functioning in difficult climatic conditions.

As an example, consider the design of the emitters of a dual-band antenna for a Powerwave cellular base station operating in the ranges 824-960, MHz and 1710-2170, MHz. Her appearance shown in the figure below:

This dual band feed consists of two metal plates. The larger one works in the lower 900 MHz band, above it is a plate with a smaller slot radiator. Both antennas are driven by slot emitters and thus have a single feed line.

If dipole antennas are used as emitters, then it is necessary to install a separate dipole for each wavelength range. Individual dipoles must have their own feed line, which, of course, reduces overall system reliability and increases power consumption. An example of such a design is a Kathrein antenna for the same frequency range as discussed above:

Thus, the dipoles for the lower frequency range are, as it were, inside the dipoles of the upper range.

For the implementation of three- (or more) band modes of operation, printed multilayer antennas have the greatest manufacturability. In such antennas, each new layer operates in a rather narrow frequency range. Such a "multi-storey" design is made of printed antennas with individual radiators, each antenna is tuned to a separate frequency of the operating range. The design is illustrated by the figure below:

As in any other multi-element antennas in this design, there is an interaction of elements operating in different frequency ranges. Of course, this interaction affects the directivity and matching of the antennas, but this interaction can be eliminated by the methods used in phased array antennas. For example, one of the most effective methods is to change the design parameters of the elements by displacing the exciting device, as well as changing the dimensions of the feed itself and the thickness of the separating dielectric layer.

An important point is that all modern wireless technologies broadband, and the operating frequency bandwidth is at least 0.2 GHz. Antennas based on complementary structures have a wide operating frequency band, typical examples of which are "bow-tie" antennas. The matching of such an antenna with the transmission line is carried out by selecting the excitation point and optimizing its configuration. To expand the operating frequency band by agreement, the "butterfly" is supplemented with an input impedance of a capacitive nature.

Modeling and calculation of such antennas is performed in specialized CAD software packages. Modern programs make it possible to simulate an antenna in a semitransparent housing in the presence of the influence of various structural elements of the antenna system and thereby allow a sufficiently accurate engineering analysis to be performed.

The design of a multi-band antenna is done in stages. First, a wide bandwidth microstrip printed antenna is calculated and designed for each operating frequency range separately. Further printed antennas different ranges combine (superimposing on each other) and consider their joint work, eliminating, if possible, the causes of mutual influence.

A wideband butterfly antenna can be advantageously used as the basis for a tri-band printed antenna. The figure below shows four different configuration options.

The above antenna designs differ in the shape of the reactive element, which is used to expand the operating frequency band by agreement. Each layer of such a three-band antenna is a microstrip emitter of predetermined geometric dimensions. The lower the frequencies, the larger the relative size of such a radiator. Each layer printed circuit board separated from the other by a dielectric. The above design can work in the GSM 1900 range (1850-1990 MHz) - it accepts the bottom layer; WiMAX (2.5 - 2.69 GHz) - accepts the middle layer; WiMAX (3.3 - 3.5 GHz) - Takes over the top layer. Such a design of the antenna system will allow receiving and transmitting a radio signal without using additional active equipment, thereby not increasing the overall dimensions of the antenna unit.

And in conclusion, a little about the dangers of BS

Sometimes, base stations of cellular operators are installed right on the roofs of residential buildings, which specifically demoralize some of their inhabitants. The owners of apartments cease to "give birth to cats", and on the head of the grandmother, gray hair begins to appear faster. In the meantime, the inhabitants of this house hardly receive an electromagnetic field from the installed base station, because the base station does not radiate "down". And, by the way, the norms of SaNPiN for electromagnetic radiation in the Russian Federation are an order of magnitude lower than in the "developed" countries of the West, and therefore, within the city, base stations never work at full capacity. Thus, there is no harm from the BS, unless you arrange to sunbathe on the roof a couple of meters from them. Often, a dozen access points installed in residents' apartments, as well as microwave ovens and cell phones (pressed to your head) have a much greater impact on you than a base station installed 100 meters outside the building.

The terms "base station" and "cell tower" have long and firmly entered our lexicon. And if the average user remembers these things not so often, then the "cell phone", by habit, is clearly among the ten leaders. Hundreds of millions of people use cellular communications every day, but very few of them think about how this very connection is provided. And of this minority, very few really represent the complexity and subtlety of this communication tool.

From the point of view of most people, setting up a cellular base station is very straightforward. It is enough to hang up a few antennas, connect them to the network - and you're done. But this view is fundamentally wrong. And so we decided to talk about how many subtleties and nuances arise when installing a base station in a metropolis.

Watch out for traffic!

To clearly illustrate our story, we have documented in detail the process of installing a cell tower on the roof of a building in Moscow, at ul. Krasnodonskaya, 19, building 2. This is a two-storey detached administrative building. We chose this example because this base station not only has a small bracket for hanging antennas, but a 5-section tower 15 m high. But let's start in order.

Preparation and design

The work of installing a base station begins with finding a suitable object. When it is found, a lease is concluded with its owner. The required location of the antennas of the future station, the mass of the payload are determined, and on the basis of this, the metal structures are designed. This takes into account the bearing capacity of the structural elements of the building itself.

For each installed base station, a set of documentation is drawn up (almost 5 cm thick). Among other things, many parameters of the future structure are indicated here: its location on the object, dimensions, the total weight, the location of the pivot points, the voltage and power consumption, and so on.

This folder contains comprehensive information:

Project documentation,
Copies of statements, licenses, certificates and statements of conformity for all elements, up to nuts and paint,
Working documentation for equipment, metal structures, architectural and construction solutions, lightning protection.
Sanitary and epidemiological conclusion on the safety of the station for residents of the surrounding houses.

Let's go back to our tower. After the agreement and approval of the project, the platform and five segments of the tower were manufactured separately at the plant. Since in this case it was a rather heavy structure, it had to be installed on the load-bearing walls of the building. For this, holes were cut in the roof and the installation of support beams was carried out. They play the role of a pile foundation for the platform, on which the station equipment and a tower with antennas were later mounted. The total weight of the platform was 3857 kg.

The profile, dimensions and number of beams from which the platform is assembled, wall thickness, length of welds, hardware used - all these parameters are calculated based on the payload mass, the bearing capacity of the building walls, as well as possible wind loads in the region. Of course, these are far from the only criteria, first of all, the tower should provide the ability to install transmit-receive antennas at the required height in the visibility range of neighboring base stations. In addition, the structure must be rigid enough so that the relay communication beam does not get lost.

Installation of metal structures

The building is small, it does not have a separate exit to the roof, so a team of installers has to climb the fire escape. Its lower part is cut off so that residents of the surrounding houses do not climb onto the roof. Unfortunately, this does not stop them too much, so something often disappears from the roofs - spare parts, cables, feeders, etc.

Despite the fact that each station is equipped with an alarm, the security service does not always have time to arrive on time.

The base station of another cellular operator has already been installed on the roof, but its dimensions cannot be compared with ours.

After installing the platform, the sites are prepared for the installation of the first section of the tower:

After the section is installed, "tightening the nuts" begins:

The installation of the tower on the studs is done in order to be able to compensate for deviations from the vertical during installation and further operation.

The verticality of the structure is constantly monitored from two points using theodolites. Moreover, measurements are carried out separately for each section of the tower, and then the measurement log will be included in the set of documents. Subsequently, periodic measurements of the tower position are carried out, since under its own weight and the weight of the equipment, a slight spiral twisting of the structure can occur (up to 50 mm at 72 m in height).

Hardware cabinet prepared for platform installation:

So, the first section is installed and aligned. Installers are preparing to receive the second section:

Great attention is paid to the safety and comfort of work not only during installation, but also during further maintenance. Platforms are sized to provide engineers with ample space to work. Ladder fences have been installed, the openings in the platforms on the tower are closed with hatches to prevent accidental falls. The platform is raised above the roof plane so that in winter time the equipment is not covered with snow and blocked by ice.

Installation of the remaining sections of the tower:

Hardware cabinet queue:

The tower has been mounted, the last measurements have been made using theodolites. Deviations are minimal and strictly within tolerances. The mass of the tower was 2827 kg, and the total weight of all metal structures was 6684 kg.

The colors of the sections are standard: the bottom and top are always red, the intermediate ones alternate with white. At the top you can see 4 pins, which are a continuation of the edges of the tower - these are lightning protection elements.

Equipment

The next step was the installation of all the necessary equipment and cabling. Full list installed equipment:

As a result, the station acquired a rather majestic appearance, especially in comparison with the building itself:

The station is supplied with a voltage of 380 V (3 phases), which is then converted into 48 V. The power is taken with a margin of up to 10 kW. Meals are supplied in a separate locker.

Let's open the door of the hardware cabinet. It has a built-in air conditioner (top) and a heater (bottom).

The cabinet maintains a temperature of 18 ... 20 degrees Celsius throughout the year. This is necessary for the smooth operation of the equipment and the long service life of the batteries (they are located at the bottom).

The accumulators are designed to ensure the operation of the station for about a day in the event of a disconnection of the external power supply.

Above is the switching unit and voltage converter.

The transfer of information between system modules and transceivers (about them below) is carried out via fiber optic cables. This is what the connector looks like in the junction box. In no case should you touch it with your hands, the fiber is very sensitive to damage and pollution.

Everything base stations of cellular communication are connected to a single information fiber-optic network stretched throughout Moscow. The white bay under the equipment cabinet is just the cable through which this station is connected.

To the right of the cabinet are the GSM, CDMA and LTE system modules:

These modules are the heart of the base station; they receive the signal from the antennas and convert and compress it with further transmission. They are not afraid of precipitation, all connectors are sealed, and the operating temperature range is from +60 to -50.

Lightning arresters are located under the system modules, which prevent equipment burnout in the event of a lightning strike:

On the right, above the modules, there are fiber-optic cable coils, with the help of which they are connected to the transceivers on the tower.

Let's move on to the tower. It has transceivers installed separately for each band (GSM, CDMA and LTE). They amplify the signal from extremely low values up to 115-120 dB. They are powered from the equipment cabinet:

The oblong vertical "boxes" are the antennas. They are shielded at the back to protect operating personnel from electromagnetic radiation. Let's go up to the site.

GSM transceiver:

CDMA transceiver:

LTE transceiver:

At the edges, fiber-optic cables are connected to the transceiver, in the center - power supply:

Grounding is brought to the tower:

Cable connectors and their plugs on the antenna:

Basic circuit diagram of base station equipment switching:

We have already mentioned that designing and building a cellular base station is not at all as easy as it seems to the uninitiated. There are many nuances that are associated with the specific location of the station. For example, radio transmission over a large water surface is deteriorating, although it should be the other way around, because there are no obstacles. But the fact is that an electromagnetic field spreads over the surface of the earth, and a large volume of water works as a kind of condenser, over which interference to the radio signal is amplified. And there are many such subtleties, therefore the efficiency of the base station directly depends on the professionalism of the designers and installers. For example, from people like this foreman of installers, a high-class radio engineer, and just a wonderful person: