Detailed explanation of 5g working principle (explanation & illustration)

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All of this , From one “ Magical formula ” Speaking of , That's the formula ！

Remember this formula , Please clap your hands proudly ,

If you don't remember , Or I can't understand , It doesn't matter ,“ A popular science ” Explain it. .

It's this super simple formula , It contains the breadth and depth of our wireless communication technology , No matter the past goes with the wind 1G、2G、3G, Still in high spirits 4G、5G, He said it , It's all about this mathematical formula .

The cable ？ wireless ？

Communications technology , No matter what black technology, white Technology , There are only two kinds —— Wired communication and wireless communication , I'm calling you , Information and data are either transmitted over the air （ Can't see 、 Unable to touch ）, Or in kind （ visible 、 I can feel it ）.

Spread data over wired media , It's easy to get high speed , In the lab , The maximum speed of a single optical fiber has reached 26Tbps, It is 26000 times of the traditional network cable .

And the airborne part , Is the bottleneck of mobile communication , therefore ,5G The focus is on the wireless part Break through the bottleneck .

What a big wave

Everybody knows , Both radio waves and light waves belong to electromagnetic waves , The frequency resources of electromagnetic waves are limited , According to different frequency characteristics , There are different uses .

At present, we mainly use Air waves communicate . Of course , Lightwave communication is also on the rise , For example, visible light communication LiFi（LightFidelity）

Back to the radio , Electric wave belongs to a kind of electromagnetic wave , Its frequency resources are also limited , To avoid interference and conflict , We are on the radio “ highway ” Go one step further “ Vehicle Lane ”, Assigned to different objects and purposes .

The use of radio waves of different frequencies

Notice the red font in the above figure . all the time , We mainly use Intermediate frequency ~ UHF Carry out mobile communication , For example, it is often said that “GSM900”、“CDMA800”, In fact, it is the working frequency band 900MHz and 800MHz It means .

At present, the mainstream 4G LTE, It belongs to UHF and UHF , Our country mainly uses UHF ：

With 1G、2G、3G、4G The development of , The frequency of use is higher and higher , Why? ？ Because the higher the frequency , The faster the speed. （ The velocity here is not the velocity of electromagnetic wave , It's the traffic transmission speed ）, And why ？ Because the higher the frequency , Vehicle Lane （ Frequency band ） The wider .

I see , The lanes expand exponentially .

Higher frequency → More bandwidth → Faster speed

5G What is the specific frequency band ？

Our Ministry of industry and information technology issued a notice , It clarifies China's 5G initial If band ：

3.3-3.6GHz、4.8-5GHz Two bands

meanwhile ,24.75-27.5GHz、37-42.5GHz High frequency band Soliciting opinions .

at present , It is mainly used internationally 28GHz Carry out experiments （ This frequency band may also become 5G The first commercial frequency band ）, If the 28GHz To calculate , According to the previous formula ：

All right. , This is 5G The first technical feature of .

Millimeter wave

since , High frequency, so good , You must ask ：“ Why didn't we use high frequency before ？”

The reason is simple —— It's not that I don't want to use , It doesn't work .

A remarkable feature of electromagnetic waves ： The higher the frequency is. （ Shorter wavelength ）, It's getting closer to a straight line （ The worse the diffraction ability ）. and , The higher the frequency is. , The greater the attenuation in the process of propagation .

Look at the laser pen （ wavelength 635nm about ）, The light is straight , If you block it, you can't get through .

Look at satellite communications and GPS Navigation （ wavelength 1cm about ）, If there is a shelter , There will be no signal .

and , The big pot of satellite , The direction of aiming at the satellite must be calibrated , A little crooked , Will have an impact .

If 5G Use high frequency band , So its biggest problem , That is, the coverage capacity will be greatly reduced .

Covering the same area , The number of base stations required will greatly exceed 4G.

This is why these years , telecom 、 Move 、 Unicom is fighting for low frequency band , A base station costs money to buy , Can we not fight with our lives ？

Some bands are even called —— The golden band .

That's why 5G Time , Operators are desperate to contact equipment suppliers , Even threatened to develop their own communication equipment .

therefore , For the above reasons , Under the premise of high frequency , In order to reduce the cost pressure of coverage ,5G We must find a new way out , The first is the micro base station .

Micro base station

There are two types of base stations , Micro base station and macro base station （ Just look at the name , The micro base station is very small , Acer station is very big ）.

It used to be a big base station , Build one to cover a large area .

In the future, more will be micro base stations , Everywhere , Can be seen everywhere .

Micro base station —— Does it look cool ？

There are many shapes of micro base stations , Flexibly integrate with the surrounding environment （ camouflage ）, It will not cause psychological discomfort to users .

remind ——

The base station will not affect human health .

and , On the contrary , In fact, the more base stations , The less radiation ！

Think about it , winter , In the house of a group of people , A high-power heater is good , Or a few small power heaters ？

High power scheme

Low power scheme

The smaller the base station , The more the number of , The better the coverage , The faster .

Where's the antenna ？

Have you noticed that , before “ mobile ” There are long antennas , Early mobile phones also had small antennas protruding out of them , Why can't we see mobile phones with antennas later ？

Some people say , Because the signal is good , There is no need for an antenna . It's not true , No matter how good the signal is , Nor can there be no antenna . The main reason is —— The antenna is getting smaller .

According to the antenna characteristics , The length of the antenna should be proportional to the wavelength , Around the 1/10~1/4 Between .

The higher the frequency is. , Shorter wavelength , So the antenna becomes shorter ！ Millimeter wave , The antenna also becomes millimeter . That means , The antenna can be stuffed into the mobile phone , You can even plug a lot of them , This is it. 5G The third killer mace of .

Ｍassive MIMO

MIMO Namely “ More in, more out ”（Multiple-Input Multiple-Output）, Multiple antennas transmit , Multiple antennas receive .

stay LTE There have been times MIMO 了 ,5G Continue to carry forward , It has become an enhanced version Massive　MIMO（Massive： On a large scale , a large number of ）.

Mobile phones can be stuffed with many pieces , Not to mention the base station .

Previous base stations , There are only a few antennas .

5G Time , It's not based on the root , Is in accordance with the “ front ”,“ Antenna array ”.

There are so many antennas in array , At a glance, there is a large rhythm .

however , The distance between antennas should not be too close . Because antenna characteristics require , Multi antenna array requires the distance between antennas to be kept more than half a wavelength .

Don't ask me why ？ Because I don't know .

You are straight ？ Still curved ？

Everyone has seen the light bulb glow ？

Actually , When the base station transmits a signal , It's kind of like a light bulb .

The signal is sent all around , For light , Light up the whole room, of course , If you just want to illuminate an area or object , that , Most of the light is wasted .

So is the base station , A lot of energy and resources are wasted .

Can we find an invisible hand , Tie up the scattered light beam ？

This saves energy , It also ensures that there is enough light in the area to be illuminated .

The answer is ： Sure .

This is it. —— Beamforming

Beam forming deploy antenna array on the base station , adopt Control of RF signal phase , It makes the lobe of electromagnetic wave after interaction very narrow , And point to the phone it serves , And can change direction according to the mobile phone . This spatial reuse technology , From omnidirectional signal coverage to precise directional service , There is no interference between beams , Provide more communication links in the same space , Greatly improve the service capacity of the base station .

Straight ones can be broken into curved ones , What else can not be done by the communication brick family ？

Don't charge me , OK? ？

In the current communication network , Even if two people dial each other's cell phone face to face （ Or send photos by mobile phone ）, Signals are relayed through the base station , Including control signaling and data packets .

And in the 5G Time , This is not necessarily the case ,5G The fifth feature of ——D2D, That is to say Device to Device.

Ｄ２Ｄ

5G Time , Two users in the same base station , If you communicate with each other , Their data will no longer be forwarded through the base station , Instead, it goes directly from cell phone to cell phone .

such , It saves a lot of air resources , It also reduces the pressure on the base station . however , If you feel this way, you don't have to pay , Then you ...

The control message still needs to go from the base station , And use spectrum resources , How can they let you go at this time ...

I'm sure you're right 5G And the communication knowledge behind it has been deeply understood , And all this , It all comes from a mathematical formula that primary school students can understand today （ Look again ）.

Communication technology is not mysterious ,5G As the most dazzling gem in the crown of communication technology , Nor is it an unreachable innovative revolutionary technology , It is more an evolution of the existing communication technology .

As an expert said —— The limits of communication technology , It's not a technical limitation , It's based on rigorous mathematics , It's almost impossible to break through in the foreseeable future .

How to be within the scope of scientific principles , Further explore the potential of communication , It is the tireless pursuit of many strivers in the communication industry .