What are the typical differences between 5G and 4G？

It all starts with a "magic formula"...

That's the formula...

If you still remember the formula, please proudly clap for yourself...

If you do not remember, or do not understand, it does not matter, let me explain to you simplly...

This super simple formul contains wireless communication extensive and profound...

No matter the past events like 1G, 2G, 3G, or hot 4G and 5G are all based on this mathematical formula.

The cable? Wireless?...

Communications technology, no matter what the black and white technology, there are only two kinds -- wired and wireless

When I'm on the phone with you, the data is either airborne (invisible) or physical (visible)...

Spreading data over wired media is easy to do at high speeds...

In the lab, the maximum speed of a single fiber has reached 26Tbps...26,000 times of traditional cable...

And the air spread is where the bottleneck is...

Therefore, 5G focuses on the bottleneck breakthrough in wireless.

As we all know, radio waves and light waves are electromagnetic waves...

Electromagnetic waves have limited frequency resources and have different USES according to different frequency characteristics...

We are currently using radio waves for communication...

Of course, light wave communication is also on the rise, such as visible light communication, LiFi (LightFidelity).

All right, back to the radio waves...

Wave belongs to a kind of electromagnetic wave, its frequency resource is also limited...

In order to avoid interference and conflict, we further divided the lanes along the airwave highway, and assigned them to different objects and purposes...

Use of radio waves of different frequencies

Notice the red font in the picture above.All the time, we mainly use midband, UHF for mobile phone communication...

For example, "GSM900" and "CDMA800" are actually operating at 900MHz and 800MHz...

The current mainstream 4G LTE belongs to VHF and UHF...

With the development of 1G, 2G, 3G and 4G, the frequency of use is higher and higher...

Why is that?

Because the higher the frequency, the faster the speed...

Why is that?

Because the higher the frequency, the wider the lane...

Higher frequency → greater bandwidth → faster speed

What exactly is 5G frequency band going to be?

Last month, the Ministry of Industry and Information Technology (MIIT) issued a notice specifying the initial intermediate frequency band of 5G in China:

3.3-3.6GHz and 4.8-5ghz frequency bands

Meanwhile, comments are being solicited for the 24.75-27.5GHz and 37-42.5GHz hf bands.

Currently, 28GHz is mainly used internationally for testing (this band may also become the first commercial band of 5G).

If it is calculated at 28GHz, according to the formula mentioned above:

This is the first technical feature of 5g——

Millimeter wave

Since high frequency is so good, you must ask, "why didn't we use high frequency before?"

The reason is simple - it's not that you don't want to use... Just we can't afford it...

A remarkable feature of electromagnetic waves is that the higher the frequency (the shorter the wavelength), the closer to the straight line propagation (the worse the diffraction ability)...

Moreover, the higher the frequency, the greater the attenuation in the propagation process...

If you look at the laser pen (wavelength 635nm), the light emitted is straight. If you block it, you can't cross it...

Look at satellite communication and GPS navigation (wavelength is about 1cm). If there is any obstruction, there will be no signal...

What's more, the satellite's cauldron must be calibrated and aimed at the satellite's direction... A little bit crooked, will have an effect...

If 5g uses high frequency band, the biggest problem is that the coverage capacity will be greatly reduced.

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

This is the reason China Telecom, China Mobile and China Unicom have been fighting for the low frequency band in recent years...

The base station is to spend money to buy... Can you fight for it without risking your life...

Some frequency bands are even called golden bands...

This is also why in the 5g era, operators are struggling with equipment providers...

Even threatened to develop their own communications equipment...

So, for the above reasons...

Under the premise of high frequency, in order to reduce the cost pressure of coverage, 5g must find a new way out...

First of all, it is the micro base station.

Micro base station

There are two kinds of base stations, micro base station and macro base station. From the name, the micro base station is very small, and the macro base station is very large!

In the past, they were all large base stations, and they were built to cover a large area

In the future, more and more micro base stations will be installed everywhere and can be seen everywhere.

Does micro base station look cool?

There are many types of micro base stations, which can be flexibly integrated with the surrounding environment (disguise) and will not cause psychological discomfort to users. . .

Remind!

The base station will not affect human health.

Moreover, on the contrary, in fact, the more the number of base stations, the smaller the radiation!

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

The smaller the base station and the greater the number, the better the coverage and the faster the speed. . .

Where did the antenna go?

Have you noticed that the big brothers used to have very long antennas, and early mobile phones also had small antennas that protruded. Why didn’t we see mobile phones with antennas later?

Some people say it's because the signal is good and there's no need for an antenna...

It's not right... No matter how good the signal is, it can't be without an antenna...

The main reason is that the antenna is getting smaller...

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

The higher the frequency, the shorter the wavelength, the shorter the antenna!

Millimeter wave, antenna also becomes millimeter level...

This means that the antenna can be plugged into the inside of the mobile phone, or even many...

This is 5g's third killer——

Ｍassive MIMO

MIMO is "multiple input multiple output", multiple antennas transmit and multiple antennas receive.

In the LTE era, there has been MIMO, 5g continues to carry forward and become the enhanced version of massive MIMO (massive: large-scale, large-scale).

Mobile phones can be plugged in more than one base station...

In the past, there were only a few antennas in the base station...

However, the distance between antennas should not be too close.

Due to the requirements of antenna characteristics, the distance between antennas should be kept at more than half a wavelength.

Don't ask me why, ask scientists...

Are you straight? Or curved?

Have you ever seen a light bulb glow?

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

The signal is sent around. For light, of course, it is to illuminate the whole room. If you just want to light up an area or an object, then most of the light is wasted...

Base station is the same, a lot of energy and resources are wasted.

Can we find an invisible hand to bind the scattered beams?

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

The answer is: Yes.

This is it——Beamforming

Beam forming:

The antenna array is arranged on the base station. By controlling the RF signal phase, the lobe of the electromagnetic wave after interaction becomes very narrow, and points to the mobile phone it provides services, and can change direction according to the mobile phone's movement.

This spatial multiplexing technology changes from omni-directional signal coverage to accurate directional service, without interference between beams, providing more communication links in the same space, and greatly improving the service capacity of base stations.

Straight can be broken into a curve... What else can't be done by communication brick?

Don't charge me, will you?

In the current communication network, even if two people dial each other's mobile phone face to face (or vice versa), the signals are transferred through the base station, including control signaling and data packets...

In the 5g era, this situation is not necessarily...

The fifth feature of 5g is D2D, which is device to device.

Ｄ２Ｄ

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

In this way, a lot of air resources are saved and the pressure of base station is reduced.

But if you think you don't have to pay for it, you're breaking Tucson...

The control message still needs to go from the base station, and with spectrum resources, how can the operator's father let you go...

I believe that you have a deep understanding of 5g and her communication knowledge through this article, and all these are just from a mathematical formula that can be understood by primary school students today...

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

As an expert said——

"The limit of communication technology is not the limit of technology and technology, but the inference based on rigorous mathematics, which is basically impossible to break through in the foreseeable future."

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

Emdoor have applied the 5G into our tablet and laptop, If ou are interested in 5G, welcome comments below.