Why doesn't the iPhone 12 of the Bank of China support millimeter waves?

This week, iPhone 12 went on sale, which is Apple's first mobile phone supporting 5G signals. Android platforms, such as Huawei, Samsung, Xiaomi, OPPO, vivo and other brands, began to sell a large number of 5G mobile phones as early as 20 19.

In the face of new technologies, especially in the field of communications, Apple has always been very conservative. 3G mobile phone went on the market in 2008, and 4G mobile phone was 20 12, which was generally slower than Android platform 1-2 years.

The strategy is that on the one hand, the relationship between Apple and Qualcomm is tense because of patent fees, while Intel, a hardcore partner, is really average in network signal technology.

As a result, the signal of Apple's mobile phone is not a little bit worse than that of a large number of Android phones with Qualcomm chips, and it is even more helpless in the aspect of 5G network.

After clarifying the facts with Qualcomm, Apple finally made its iPhone support 5G network.

As far as paper parameters are concerned, the iPhone 12 released by Apple this time really supports quite comprehensively in the 5G band: from n 1, n2, n3, n5, n7, n8…… ... all the way to n7 1, n77, n78, n79, and n260, N260, and N260 in the millimeter wave band.

So the question is, what do these band numbers mean? What does millimeter wave mean? I heard that millimeter wave is more powerful. Why doesn't our version iPhone 12 support millimeter wave?

To understand these problems, we should start with the basic principles of 5G network signals.

When it comes to 5G, we all know that its remarkable characteristics are fast, fast network speed, fast response and low delay.

This is supported by a simple physical formula: c = λ v.

Light speed = wavelength frequency.

The speed of light is constant, so the wavelength is inversely proportional to the frequency. The reason why 5G is fast is that as an electromagnetic wave, its frequency is higher than that of 4G network. Therefore, its wavelength is short.

The electromagnetic waves we use for wireless communication are generally in the low frequency band below the visible light band of human eyes. This band looks very wide, but the resources are very limited. Because we have too much to do with this band.

Think about it, radio, TV signals, cell phone signals, Wi-Fi signals and Bluetooth signals sent by public institutions are all in this frequency band.

But as long as they are waves, they will collide and interfere with each other, just like when we throw several stones into a pool, the water waves splashed by them will overlap or cancel each other. Without planning, everyone will throw stones and influence each other. In the end, no one's wave can be transmitted.

The best way is segmentation. Everyone agrees that waves with a certain wavelength and frequency can only do one thing. Just like dividing lanes on an expressway, no one should press the line. In this way, pedestrians, bicycles and cars go their separate ways. Although their speeds are different, they will not affect each other.

In the field of wireless communication, such as the low frequency band of 30-300 kHz, it is mainly used for cross-sea communication. Because of the longer wavelength, they are easier to bypass obstacles and are more suitable for long-distance communication.

The frequency band used by our mobile phone communication is the intermediate frequency to ultra-high frequency of the radio band.

For example, the so-called GSM900 in the 2G era is a GSM network with a working frequency band of about 900MHz, and GSM 1800 is a GSM network with a working frequency band of about 1800MHz. At that time, the so-called dual-band mobile phone was a 2G mobile phone that supported two frequency bands.

In the 3G era, the so-called CDMA2000 is a CDMA network with a frequency band of about 2000MHz. LTE in the 4G era is an LTE network with a frequency band of about 2500MHz.

You will find that with the upgrade of communication network, that is, the so-called upgrade of 2G, 3G and 4G, the frequency of radio waves we use is getting higher and higher, and the communication speed is getting faster and faster.

What is the frequency of 5G in the current 5G era?

The frequency range of 5G is divided into two parts:

One is the part with frequency below 6GHz, and the technical term is Sub-6GHz.

According to this definition, look back at the 2G, 3G and 4G networks we just mentioned, all in this frequency band, but 5G is higher than their frequencies.

For example, China Unicom obtained the 5G band of 3.4G-3.5GHz with the band number n78, while China Telecom obtained the band of 3.5G-3.6GHz with the band number n78.

China Mobile is a little more complicated, and has got two frequency bands, namely n4 1 band around 2.5G-2.6GHz and n79 band around 4.8G-4.9GHz.

It is worth noting that China Mobile's n79 and China Radio and Television's n79 band numbers are the same. However, the n79 of China Radio and Television is a little higher than that of China Mobile, which is 4.8G-4.9GHz, while that of China Radio and Television is 4.9G-4.96GHz.

After understanding these concepts, let's take a look at the detailed parameters of 5G mobile phones on the market. In the column of supporting 5G frequency band, there is generally a description of "supporting n4 1 and n78".

Corresponding to the content just now, you will find that as long as it supports the n78 band, it means that this phone supports both China Unicom and China Telecom's 5G. As long as n4 1 is supported, it means that some frequency bands of China Mobile are supported.

So in other words, a so-called "Three Netcom" 5G mobile phone only needs to support n4 1 and n78.

If the n79 band can be supported, it means that the high-frequency 5G signals of China Mobile and China Radio and Television are also supported, and the network speed will be faster where the signals in this band can be received.

Of course, this "faster" is relative, but it is faster in the range below 6GHz.

The most anticipated 5G network is the frequency band above 24GHz. The pre-5G test was 28GHz. Divide the speed of light by 300 million meters per second, and you will find that the wavelength of 5G signal at this frequency is only about10 mm. ..

This is another component of 5G signal, millimeter wave.

Of course, its transmission speed is the fastest, but at the same time, the disadvantage is that the transmission distance is very short because the wavelength is only10 mm.

"Get out of the way! You are blocking my 5G signal! " It may not be a joke here at millimeter wave.

In contrast, the wavelength of 2G signal is about 1 m, which makes it easier to bypass obstacles.

I have seen millimeter wave demonstrations in Qualcomm before. To ensure that a subway station has no dead ends, several base stations need to cooperate, because a pillar may block millimeter wave signals.

Therefore, although millimeter wave is more powerful, it is definitely not a good choice in the early stage of 5G popularization.

It should be noted here that both below 6GHz and millimeter wave are components of 5G, and there is a complementary relationship between them. Our country's strategy is to develop below 6GHz first, solve the problem of signal coverage first, and let everyone use 5G first. At the same time, millimeter wave deployment has not stopped, but is also advancing.

Almost 95% of more than 60 commercial operators in the world have adopted this scheme. In other words, in most parts of the world, there is no universal application scenario of millimeter wave in the short term.

On the contrary, the United States gives priority to the deployment of millimeter waves. Because in the United States, a large number of assignable frequency bands below 6GHz have been occupied, and there is not enough bandwidth allocated to operators.

As you can imagine, the progress of millimeter wave promotion is slow and the experience is poor. Many consumers complain that the coverage below 6GHz in the United States is not complete, millimeter wave is not as good as below 6GHz, and it is useless to buy 5G products.

Therefore, Apple's first iPhone 12 supporting 5G network may still encounter Waterloo in the domestic market of the United States, although it supports millimeter waves in other regions. There is a simple reason. The three major operators in the United States have not yet launched a truly reliable and widely covered 5G network.

Therefore, rather than saying that Apple "castrated" millimeter waves in other markets, it is better to say that the addition of millimeter waves in the US version is a helpless move to save the US market.

After all, this is the biggest selling point of the new iPhone.

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