Simple and magical formula
Today’s story, from formula begins to tell case.
This is one already simple magical formula. Say it is simple, because its altogether has 3 letters only,be. And say it is magical, because,be this formula accumulate contained broad and profound communication technology mystery, the person that there is countless on this heavenly body is in miss deeply for it.
This is formulary, it is its ——
I believe a lot of classmates know this formula, if did not recognize, and you are the word with an unfamiliar science department, the teacher of middle school physics that writes down availably how to give you please calls!
Small jujube gentleman explains, above this is formulary, this is the basic formula of physics, frequency of × of wavelengh of = of velocity of light.
Formulary to this, can so say: No matter be 1G, 2G, 3G, still be 4G, 5G, remain essentially the same despite all apparent changes, it is to be on its body entirely make an issue of, did not jump out ” of its hill of “ the five fingers.
And listen to me to slowly come. . .
Communication technology, white science and technology of whatever black science and technology, in the final analysis, it is wired communication of two kinds of —— and wireless communication with respect to cent.
I and you call, information data or travels in sky (invisible, feel do not wear) , or travels on objective (look so that see, feeling) .
If be,travel in hypostatic materially, it is wired communication, the copper cash that basically uses namely, fiber-optic these wire cable, a general designation is wired medium.
Data transmits on wired medium, rate can reach very high numerical value.
With fiber-optic for exemple, in the lab, odd a fiber-optic the oldest rate already achieved 26Tbps. . . It is 26 thousand times of reticle more traditional. . .
And Travel in sky This part, just be the bottleneck place of mobile.
At present the mobile standard of the mainstream, it is 4G LTE, theoretical rate has 150Mbps only (do not include carrier group) . This is mixed wired be to do not have method photograph completely to compare.
So, If 5G wants to achieve the high rate that carries end, the key is a breakthrough wireless this part bottleneck .
Everybody knows, wireless communication uses electromagnetic wave to have communication namely. Electric wave and light-wave, belong to electromagnetic wave.
The function of electromagnetic wave is characteristic, decide by its frequency. The electromagnetic wave of different frequency, have different attribute characteristic, have different use thereby.
For example, high frequency γ ray, have very great power, can use remedial tumour.
The ceaseless frequency of electromagnetic wave
We basically are used at present Electric wave Have communication. Of course, light-wave communication also is in rise abruptly, for example LiFi.
LiFi (Light Fidelity) , visible light corresponds
Impartiality is inscribed, return electric wave first.
Electric wave belongs to a kind of electromagnetic wave, its frequency resource is finite.
To avoid to disturb and conflict, we are in electric wave this Highway Go up to differentiate further Driveway , allocate different object and utility.
The utility of different frequency electric wave
Ask the gules font that everybody pursues medium above the attention. All the time since, we basically are to use Intermediate frequency ~ exceeds High frequency Undertake the mobile phone corresponds.
Often say for example“ GSM900 ” , “ CDMA800 ” , actually the meaning points to namely, working frequency paragraph the GSM in 900MHz, with working frequency paragraph the CDMA in 800MHz.
At present the standard of 4G LTE technology of global mainstream, belong to VHF and UHF.
Our country basically uses ultrahigh frequency:
Everybody can see, as the development of 1G, 2G, 3G, 4G, use electric wave frequency is taller and taller.
Is this why?
Because,this basically is, Frequency is taller, the frequency resource that can use is richer. Frequency natural resources is more substantial, the transmission rate that can achieve is higher.
Taller frequency→ More resource→ Faster speed
Not should fathomless? Frequency resource resembles railroad car, jump over tall frequency, railroad car is more, the information that lades with time internal energy is more.
So, is the frequency that 5G uses specific how much be?
Following plan institute show:
The frequency limits of 5G, cent is two kinds: One kind is 6GHz the following, this is mixed at present the difference does not consider our 2/3/4G too big. Still have a kind, very tall, in 24GHz above.
Current, main use 28GHz has a test on international (this frequency paragraph become 5G likely also most first commercial frequency paragraph) .
If press 28GHz to calculate, what according to preamble we mention is formulary:
Good, this is the — of characteristic of the first technology of 5G—
Allow my reappearance please a moment ago that frequency contrasts watch:
Notice to look please most below group, it is “ millimeter wave” ?
Good, since, frequency is tall so good, you can ask certainly: “ why previously us need not Where is high frequency rate? ”
The reason is very simple —— is not not to want to use, it is to use do not rise.
The marked characteristic of electromagnetic wave: Frequency is taller, wavelengh is shorter, jump over hasten to be bordering on linear transmission (diffraction ability is poorer) . Frequency is taller, the attenuation in transmitting medium is bigger also.
You see laser pen (wavelengh 635nm is controlled) , the light that shoots is straight, held off was impassable.
See satellite communications and GPS navigation again (wavelengh 1cm is controlled) , if have keep out thing, do not have signal.
Satellite that caldron, must calibration is taking aim satellitic direction, otherwise even if a little a bit more crooked, can affect signal quality.
If mobile was used high frequency paragraph, so its biggest question, namely Transmission distance shortens considerably, Covering power considerably abate .
Enclothe same an area, the 5G of need base station amount, will exceed 4G greatly.
Base what does station amount mean? Money! Investment! Cost!
Frequency is lower, network construction jumps over be economical, competition rises more advantageous. This is why, these year, telegraphic, mobile, UniCom for low frequency paragraph and contend for head broken and bleedingly.
Some frequency paragraph be called even —— Gold frequency paragraph .
This also is why, 5G times, operation business rancors desperately equipment business, hope radical station depreciates. (if go up really 5G, press before mode, equipment business sends big money. )
So, be based on above reason, below high-frequency premise, build the cost pressure of the respect to reduce a network, 5G must search new outlet.
What does the outlet have?
Above all, it is small base station.
Base the station has two kinds, small base station He Hongji stands. See a name know, small base the station is very small, grand base the station is very big!
Grand base station:
Outdoor common, build to enclothe a big
Small base station:
Is looking very does cruel dazzle?
Still have smaller, hand is so old
Actually, small base the station has now many, especially the city zone and indoor, often can see.
After, arrived 5G times, small base the station will be more, meet everywhere mount, almost everywhere is visible.
You can ask for certain, so much base the station is beside, can you cause an effect to human body?
My answer is —— won’t.
Actually, with traditional acknowledge apropos and contrary, in fact, base station amount is more, radiation is smaller instead!
You think, in the winter, in the house of a flock of people, a high-power warms oneself implement good, be still a few small-power warms oneself implement good?
High-power plan ▼
Small-power plan ▼
The graph above, be clear at a glance. Base the station is small, power is low, good to everybody. If use only big base station, leave nearly, radiation is big, leave far, do not have signal, bad instead.
Everybody has discovery, hand-hold portable telephone has very long antenna previously, inchoate mobile phone also has highlight the small antenna that come, why doesn’t our mobile phone have aerial now?
Actually, we are not not to need aerial, however our aerial decrescent.
According to aerial character, aerial length should become direct ratio with wavelengh, it is about between 1/10~1/4.
Change as time, the communication frequency of our mobile phone is taller and taller, wavelengh is shorter and shorter, aerial also shortens accordingly!
Millimeter wave corresponds, aerial also turns millimeter into class. . .
This is meant, aerial can fill in completely inside receive a mobile telephone, can fill in even a lot of. . .
This is the — of mace of the 3rd big killer of 5G—
M Assive MIMO (much antenna technology)
MIMO is “ enter many ” more (Multiple-Input Multiple-Output) , much root antenna is sent, much root antenna is received.
In LTE times, we had had MIMO, but aerial amount does not calculate much, can say the MIMO that is primary edition only.
Arrived 5G times, continue to carry forward MIMO technology, became now strengthen of edition Massive MIMO (Massive: Large-scale, many) .
A lot of antenna can fill in inside the mobile phone, base station with respect to prep let alone.
Previously base station, aerial so a few:
5G times, aerial amount is not to press a root to calculated, it is to press “ blast ” . . . ” of “ antenna array. . . Go soon, good is concentrated the rhythm of scared disease. . .
Nevertheless, the distance between aerial also cannot too close.
Because aerial character asks, the distance between antenna of requirement of much antenna array maintains in half wavelengh above. If the distance became close, with respect to can mutual interference, affect signal send and receive .
Are you straight? Curved still?
Has everybody seen bulb shines?
Actually, base station transmit when, give off light like bulb a bit.
Signal is to all around blast off, to light, it is to enlighten of course whole room, if just want to enlighten a certain area or object, so, major light was wasted. . .
Base the station also is same, much energy and resource were wasted.
We can find an invisible hand, rise ligature of diffuse beam of light?
Such already managing energy, the area that also assured to want to enlighten has enough light.
The answer is: Can.
This is ——
In base the cloth on the station sets aerial array, through To the control with radio frequency phasic signal , make the wave valve of the electromagnetic wave after interaction becomes very narrow, point to the mobile phone that it provides a service, and can follow according to the shift of the mobile phone right-about-face.
This kind of space answer uses a technology, by complete to signal is enclothed change to allow directivity to serve for essence of life, won’t disturb between beam, more communication link are provided in same space, rise greatly base the service capacity of the station.
Straight can break a turn. . . Does communication brick home do what still have not to come out?
Do not receive my fund, be no good all right?
In current mobile network, even if the mobile telephone that two people dial the other side face-to-face (or the mobile phone is right send a picture) , signal is to pass base the station undertakes change trains, include to control a letter to make be wrapped with data. . .
And in 5G times, this kind of case is not particular.
The ——D2D of the 5th big characteristic of 5G, namely Device To Device (equipment arrives equipment) .
5G times, same base two users below the station, if have communication each other, their data will be passed no longer base station transmit, however direct mobile phone arrives mobile phone. . .
Such, managing the resource in much air, also reduced base the pressure of the station.
Nevertheless, if you feel to need not pay so, then you pursue master drawing dark was defeated.
Dominate a news or want from base stand, you are using spectrum resource, operation business father lets off you how possibly. . .
Writing writing, what small jujube gentleman discovers at great length is written is a bit much. . .
Can see this, be true love. . .
Believe everybody carries the article, to 5G and her the communication knowledge of backside had had deep understanding. And all these, just result from the maths that a pupil can understand is formulary. Be?
Communication technology is not secret, 5G regards communication technology as the most dazzling gem on imperial crown, also not be the innovation revolution technology that what Yao cannot reach, its more is the gradual progress of pair of existing communication technologies.
The limit of communication technology, not be the limitation of technical craft respect, build the inference on rigorous maths foundation however, did not come to be basic impossible breakthrough in what can encounter.
How be inside the category of scientific principle, disentomb further the latent capacity of communication, it is communication industry numerous the person that struggle people assiduous pursuit.