Esta es la primera vez que alguien ha explicado el 5G de forma tan sencilla y clara.

1

A simple and magical formula

Today’s story starts with a formula.

Es una fórmula a la vez simple y mágica. Es simple porque solo tiene tres letras. Se dice que es mágica porque encierra los profundos secretos de la tecnología de la comunicación, y muchísimas personas en el planeta están obsesionadas con ella.

This formula is it——

I believe many students recognize this formula. If not, and you are a science student, please remember to call your middle school physics teacher when you have time!

Por favor, explíqueme que la fórmula anterior es una fórmula básica de la física.Speed ​​of light = wavelength & times; frequency.

Para esta fórmula, podemos decir:Whether it is 1G, 2G, 3G, or 4G or 5G, everything remains the same. They all make a fuss about it and do not jump out of its "Five Finger Mountain".

Déjame explicártelo despacio.

2

¿Con cable? ¿Inalámbrico?

Communication technology, no matter what black technology or white technology, in the final analysis, can be divided into two types——Wired communications and wireless communications.

Cuando hablo contigo por teléfono, la información y los datos se transmiten por el aire (invisibles e intangibles) o a través de objetos físicos (visibles y tangibles).

Si se transmite a través de materiales físicos, se trata de comunicación por cable, que básicamente utiliza cables de cobre y cables de fibra óptica, denominados colectivamente medios cableados.

Cuando los datos se transmiten a través de medios cableados, la velocidad puede alcanzar valores muy elevados.

Tomando como ejemplo la fibra óptica, en el laboratorio,La velocidad máxima de una sola fibra óptica ha alcanzado los 26 Tbps. . . Es 26,000 veces mayor que la de los cables de red tradicionales. . .

fibra óptica

La propagación aérea es el principal obstáculo en las comunicaciones móviles.

The current mainstream mobile communication standard is 4G LTE, with a theoretical rate of only 150Mbps (excluding carrier aggregation). This is completely incomparable to wired.

Therefore, if 5G wants to achieve high end-to-end speeds, the focus is to break through the bottleneck of the wireless part.

3

What a magical wave

Como todos sabemos, la comunicación inalámbrica utiliza ondas electromagnéticas para comunicarse. Las ondas de radio y las ondas de luz son ambas ondas electromagnéticas.

The functional characteristics of electromagnetic waves are determined by their frequency.Las ondas electromagnéticas de diferentes frecuencias tienen diferentes propiedades y características, y por lo tanto tienen diferentes usos.

For example, high-frequency gamma rays are very lethal and can be used to treat tumors.

constant frequency of electromagnetic waves

We currently communicate primarily using air waves. Of course, light wave communications are also on the rise, such as LiFi.

LiFi（Light Fidelity），可见光通信

Without digressing, let’s go back to the radio wave first.

Radio waves are a type of electromagnetic waves, and their frequency resources are limited.

In order to avoid interference and conflicts, we further divide the lanes on the radio wave highway and assign them to different objects and uses.

The uses of radio waves at different frequencies

Please pay attention to the red font in the picture above. Until now, we have mainly usedPara la comunicación por telefonía móvil se utilizan frecuencias medias y ultra altas.

For example, the often mentioned "GSM900" and "CDMA800" actually refer to GSM operating in the 900MHz frequency band and CDMA operating in the 800MHz frequency band.

The current global mainstream 4G LTE technical standard belongs toUHF and UHF.

Our country mainly uses UHF:

Como se puede observar, con el desarrollo de las tecnologías 1G, 2G, 3G y 4G, la frecuencia de las ondas de radio utilizadas es cada vez mayor.

¿Por qué es esto?

Esto se debe principalmente a que,Cuanto mayor sea la frecuencia, mayor será la riqueza de los recursos de frecuencia que se podrán utilizar.The richer the frequency resources, the higher the transmission rate that can be achieved.

Higher frequency → more resources → faster speed

No debería ser difícil de entender, ¿verdad? Los recursos de frecuencia son como vagones. Cuanto mayor sea la frecuencia, más vagones habrá y más información se podrá cargar en el mismo tiempo.

So, what is the specific frequency used by 5G?

Como se muestra abajo:

The frequency range of 5G is divided into two types: one is below 6GHz, which is not much different from our current 2/3/4G. There is another kind, which is very high.Above 24GHz.

Currently, internationally, it is mainly used 28GHz Conduct experiments (this frequency band may also become the first commercial frequency band for 5G).

If calculated based on 28GHz, according to the formula we mentioned above:

Okay, this is the first technical feature of 5G——

4

onda milimétrica

Please allow me to repost the frequency comparison table just now:

Por favor, preste atención a la última línea. ¿Es "onda milimétrica"?

¡Vamos, vamos!

Bueno, dado que la alta frecuencia es tan buena, seguramente preguntarás:"Why didn't we use high frequencies before?"

La razón es sencilla: no es que no quiera usarlo, es que no me lo puedo permitir.

The salient characteristics of electromagnetic waves: the higher the frequency, the shorter the wavelength, and the closer it is to linear propagation (the worse the diffraction ability).Cuanto mayor sea la frecuencia, mayor será la atenuación en el medio de propagación.

Look at the laser pointer (wavelength is about 635nm). The light emitted is straight. If it is blocked, it will not be able to pass through.

Looking at satellite communications and GPS navigation (wavelength is about 1cm), if there are obstructions, there will be no signal.

The big pot of a satellite must be calibrated to aim at the direction of the satellite, otherwise even a slight deviation will affect the signal quality.

If mobile communications use high frequency bands, then its biggest problem isLa distancia de transmisión se reduce considerablemente y la capacidad de cobertura se debilita notablemente.

covering the same area,The number of 5G base stations required will greatly exceed that of 4G.

What does the number of base stations mean? Money! Invest! The cost!

Cuanto menor sea la frecuencia, más barata será la construcción de la red y más favorable será la competencia. Por eso, en los últimos años, China Telecom, China Mobile y China Unicom han estado compitiendo ferozmente por las bandas de baja frecuencia.

Some frequency bands are even called——Golden band.

This is why, in the 5G era, operators are desperately fighting against equipment manufacturers, hoping to reduce the price of base stations.

Por lo tanto, sobre la base de las razones anteriores, con el fin de reducir la presión de costos en la construcción de la red bajo la premisa de alta frecuencia,5G must find a new way out.

What are the ways out?

En primer lugar, está la microestación base.

5

micro base station

Existen dos tipos de estaciones base: microestaciones base y macroestaciones base. ¡Como su nombre indica, la microestación base es muy pequeña y la macroestación base es muy grande!

Macro base station:

Es común en exteriores, construya uno para cubrir una gran área.

Microestación base:

Doesn’t it look cool?

Incluso hay ejemplares más pequeños, del tamaño de una palma.

In fact, there are many micro base stations now, especially in urban areas and indoors, where they are often seen.

In the 5G era, there will be more micro base stations, which will be installed everywhere and can be seen almost everywhere.

You will definitely ask, will there be any impact on the human body if there are so many base stations around us?

My answer is - no.

In fact, contrary to traditional understanding, in fact,The greater the number of base stations, the smaller the radiation!

Think about it, in winter, in a house with a group of people, is it better to have one high-power heater or several low-power heaters?

Solución de alta potencia▼

Low power solution▼

The picture above is clear at a glance.The base station is small and low-power, which is good for everyone.Si solo se utiliza una estación base grande, si está cerca, la radiación será grande, pero si está lejos, no habrá señal, lo cual no es bueno.

6

¿Dónde está la antena?

Have you noticed that mobile phones used to have very long antennas, and early mobile phones also had small protruding antennas. Why do our mobile phones now have no antennas?

De hecho, no es que no necesitemos antenas;The antenna got smaller.

Según las características de la antena, la longitud de la antena debe ser proporcional a la longitud de onda, aproximadamente entre 1/10 y 1/4.

Con el paso del tiempo, la frecuencia de comunicación de nuestros teléfonos móviles es cada vez mayor, la longitud de onda es cada vez menor, ¡y las antenas también son cada vez más cortas!

For millimeter wave communication, the antenna has also become millimeter level. . .

This means that the antenna can be inserted into the mobile phone, or even many antennas can be inserted. . .

This is the third biggest killer feature of 5G——

7

ＭMIMO pasivo

(Multi-antenna technology)

MIMO is "Multiple-Input Multiple-Output" (Multiple-Input Multiple-Output), multiple antennas transmit and multiple antennas receive.

In the LTE era, we already had MIMO, but the number of antennas was not large. It could only be said to be a junior version of MIMO.

In the 5G era, MIMO technology continues to be developed, and now it has become an enhanced version of Massive MIMO (Massive: large-scale, massive).

There are multiple antennas packed into a mobile phone, not to mention a base station.

En el pasado, las estaciones base solo tenían unas pocas antenas:

In the 5G era, the number of antennas is not calculated by root, but by "array". . . "antenna array". . . At first glance, it has the rhythm of trypophobia. . .

However, the distance between antennas cannot be too close.

Debido a las características de las antenas, un conjunto de antenas múltiples requiere que la distancia entre ellas se mantenga por encima de media longitud de onda. Si la distancia es menor, interferirán entre sí y afectarán la transmisión y recepción de señales.

8

formación de haces

Everyone has seen a light bulb glow, right?

In fact, when the base station transmits a signal, it is a bit like a light bulb glowing.

The signal is emitted to the surroundings. For light, of course it illuminates the entire room. If you just want to illuminate a certain area or object, then most of the light is wasted. . .

Lo mismo ocurre con las estaciones base, donde se desperdician muchos recursos y energía.

¿Podemos encontrar una mano invisible que ate la luz dispersa?

This not only saves energy, but also ensures that the area to be illuminated has enough light.

La respuesta es sí.

This is - beamforming

An antenna array is arranged on the base station, and by controlling the phase of the radio frequency signal, the lobe of the electromagnetic wave after interaction becomes very narrow and pointed at the mobile phone it provides services, and can change the direction according to the movement of the mobile phone.

This spatial multiplexing technology changes from omnidirectional signal coverage to precise directional service without interference between beams.Provide more communication links in the same space, greatly improving the service capacity of the base station.

Straight ones can be broken into curved ones. . . Is there anything else that communication experts can’t do?

9

Don't charge me any money, okay?

In the current mobile communication network, even if two people call each other's mobile phones face to face (or send photos to each other through mobile phones), the signals are relayed through the base station, including control signaling and data packets. . .

In the 5G era, this is not necessarily the case.

The fifth major feature of 5G is D2D, which is Device to Device.

10

Ｄ２Ｄ

In the 5G era, if two users under the same base station communicate with each other, their data will no longer be forwarded through the base station, but directly from mobile phone to mobile phone. . .

De esta forma, se ahorra una gran cantidad de recursos aéreos y se reduce la presión sobre la estación base.

However, if you think you don’t have to pay, then you are doing Tucson a disservice.

Control messages still have to go from the base station. You are using spectrum resources. How can the operator let you go? . .

posdata

I believe that through this article, everyone has a deep understanding of 5G and the communication knowledge behind it. And all of this is just based on mathematical formulas that a primary school student can understand. Isn't it?

Communication technology is not mysterious. As the most dazzling gem in the crown of communication technology, 5G is not an out-of-reach innovative revolutionary technology. It is more of an evolution of existing communication technology.

As an expert said -

The limits of communication technology are not limitations in technical technology, but inferences based on rigorous mathematics. It is basically impossible to break through in the foreseeable future.

How to further explore the potential of communications within the scope of scientific principles is the tireless pursuit of many strivers in the communications industry.

Okay, that’s it for today.

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