Behind the new 5g upgrade of iPhone 12, there may be a lot of things you don't know.
Last week, the belated iPhone 12 series was finally released, although a month later than usual, but the heat is still the same year, you can observe a very interesting phenomenon, once the new iPhone is released, you rarely see "next time" complaints, on the contrary, many people will use real gold and silver evidence to show its popularity
As the focus of this upgrade, 5g network support is naturally the most concerned point of consumers, and also the main factor behind the hot sell out. However, there may be many things you don't know behind the new 5g upgrade of iPhone 12.
Why does the US version of iPhone 12 have more "small patches"?
Careful friends may find that there is a special detail on the US version of iPhone 12 which is different from other versions. Only from the appearance, we can observe the subtle difference. There is a "small patch" on the lower right side of the US version iPhone 12.
The patch was mistaken for a Touch ID fingerprint identification module in previous revelations, and after the press conference, many people discussed the Apple Pencil magnetic charging port
But in fact, this is just an ordinary antenna slot. So the question is, why is it only available in the US version?
In fact, this is closely related to the 5g network support in the United States. It should be understood that the 5g network frequency band in the world is mainly divided into sub-6 GHz and millimeter wave.
Sub-6 GHz is an electromagnetic wave with a wavelength of centimeter level, which can be understood as "centimeter wave". As the name implies, it occupies the network frequency band below 6GHz, while millimeter wave is the electromagnetic wave with the wavelength of millimeter level, which is usually referred to as the frequency band of 30-300 GHz, and often includes the frequency band above 24 GHz.
The millimeter wave has an absolute advantage in speed alone, and at last week's Apple press conference, the U.S. version of the iPhone 12 has a theoretical download rate of up to 4 Gbps (512MB / s) in millimeter-wave networks, which means that ideally, I can run out of traffic 30 GB a month in a minute
At present, the United States is the country that mainly promotes 5g millimeter wave. Because the data throughput of 5g millimeter wave is very high, it naturally has higher requirements for signal conditions. This also makes the antenna design of 5g millimeter wave more difficult, but at the same time, the layout space left by mobile phones is becoming smaller and smaller.
Therefore, it is not difficult to understand why there is an extra signal slot on the US version of iPhone 12. After all, only in this way can the stability of millimeter wave signal be ensured, which is also an unavoidable practice.
Millimeter wave is so powerful, why don't we use it?
In China's 5g development path, the first choice is sub-6 GHz. We mentioned earlier that due to the different characteristics of the two frequency bands, the speed of sub-6 GHz is not as good as that of millimeter wave, but we can't deny the ability of sub-6 GHz. The biggest advantage of this frequency band is strong signal penetration, wide coverage and lower cost. For example, at present, domestic 5g package charges are very affordable in the world, and operators are also vigorously launching 5g with different rates Although it is not as fast as millimeter wave, it is much faster than 4G before.
It is not difficult to find out,China's choice of sub-6 GHz as the preferred solution at this stage is also to solve the problem of 5g network coverage, and then put 5g into practical application as soon as possible, so that most consumers can use 5g network. If you want to be rich, you should build roads first.
In contrast, although the transmission speed of millimeter wave is extremely fast, it has the flavor of "strong outside but dry in the middle". It not only has high requirements on the signal of the mobile phone itself, but also has very strict requirements on the surrounding environment. Moreover, due to the small signal coverage, it needs to lay the base station with high density, so the cost of using it will be much higher.
In the "5g millimeter wave technology white paper" published by the Global Association for mobile communication systems (GSMA), the challenges faced by the current millimeter wave technology are specially emphasized, among which the first is the problem of signal coverage. China Unicom has measured this problem. According to the measured results, we can see thatThe transmission loss of 5g millimeter wave is much higher than that of sub-6 GHz, and the propagation of millimeter wave is also affected by bad weather such as rain, snow and fog.
Millimeter wave in China is ready
In fact, for the construction of 5g network, whether it is sub-6ghz or millimeter wave, there is no difference between the advantages and disadvantages of true and false, but the development sequence is different.
China's choice of sub-6 GHz at this stage is to see its stronger coverage and lower cost than millimeter wave, because the current 5g network has not been fully covered, killer 5g applications are still full of uncertainty, the significance of millimeter wave technology at this stage is not great. But from a long-term perspective, millimeter wave is definitely the main solution for hot spots in the future.
It is also mentioned in the white paper on 5g millimeter wave technology that 5g millimeter wave is easier to realize dense cell deployment than sub-6 GHz.
This makes 5g millimeter wave very suitable for large places such as conference rooms, concerts, gymnasiums, subway stations and other densely populated areas. Therefore, 5g millimeter wave and sub-6 GHz in medium and low frequency have different performance advantages, and their cooperation and complementation are the key to realize 5g complete experience.
At present, the development ecology of 5g millimeter wave industry in China is relatively complete, and it has the conditions for deployment and commercialization. We may use 5g millimeter wave network in 2022 Winter Olympic Games. At present, mainstream mobile communication equipment providers have launched base station equipment supporting 5g millimeter wave, chip manufacturers and terminal equipment manufacturers have also released some 5g millimeter wave products. For example, in the near future, the high-speed 5g millimeter wave technical performance test has been completed with the addition of mobile phones.
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Link to the original text:Geek Park