Apple has previously reached an agreement with Qualcomm, and this year's iPhone 12 support for 5G networks can be said to be firmly established. However, news shows that only two of the four new phones may support the Sub-6GHz and millimeter wave bands, and the other two only support the Sub-6GHz frequency band, not millimeter waves.
What exactly do Sub-6GHz and millimeter wave mean, and why does Apple do this? Some people say that whether the Bank of China iPhone 12 has millimeter waves will not be affected. What does this mean? Let's take a look with questions.
01 What is the difference between Sub-6GHz and millimeter wave
Sub-6GHz and millimeter wave are the two frequency band codes of 5G networks. 3GPP is one of the world's largest patent organizations. The 5G networks deployed worldwide are all 5G within the framework of 3GPP, and the 5G wireless air interface is called NR. 3GPP defines the working frequency of 5GNR in the 5G wireless specification, which is divided into two parts, FR1 and FR2.
FR1 defines 450MHz-6000Mhz, which is what we often call Sub-6GHz.
FR2 defines 24250Mhz-52600Mhz. Because most of the FR2 coverage bands are less than 10 mm in wavelength, this part of the band is also called "millimeter wave (mmWave)".
Global 5G network frequency bands are mainly divided into two major ranges: Sub-6GHz and millimeter wave. At present, my country mainly uses Sub-6GHz. The characteristics of this frequency band are: signal penetration is strong, but the data transmission speed is slower than millimeter wave. Specifically, the highest downlink rate of the chip supporting Sub-6GHz is 4.7Gbps, while the downlink rate of the chip supporting millimeter wave can reach 7.35Gbps, theoretically even a high-speed transmission of 10Gbps can be realized.
The US mainly uses the millimeter wave frequency band, which is characterized by fast transmission speed but poor penetration. How bad is that? Millimeter waves are electromagnetic waves with a wavelength between 1 millimeter and 10 millimeters. We can learn from physics classes that the higher the frequency of electromagnetic waves and the shorter the wavelength, the worse the penetration.
In this regard, some foreign digital bloggers have tested the 5G signals of T-Mobile and other operators in the United States. Among them, T-Mobile covers Sub-6GHz and millimeter wave frequency bands, while other operators mainly use millimeter wave frequency bands.
The results show that 5G mobile phones using millimeter wave technology can be blocked by almost anything, such as phone booths, glass, trees, rain, etc. As long as there is obstruction between the base station and the mobile phone, the 5G network may fall back to 4G. In contrast, operators that use both Sub-6GHz and millimeter wave coverage perform better.
All in all, Sub-6GHz and millimeter wave represent two large ranges of 5G wireless frequencies. At present, China's 5G construction is dominated by Sub-6GHz, while the United States is dominated by millimeter waves. This is also the current two directions of global 5G development.
02 Current status of Sub-6GHz and millimeter wave applications
At this stage, my country has chosen the Sub-6GHz frequency band to develop 5G, the United States mainly chooses the millimeter wave frequency band, and South Korea, Japan, Europe and other countries or regions are developing both frequency bands. Sub-6GHz and millimeter waves are complementary, not iterative. Just like the data cellular network and Wi-Fi, network construction depends on the specific needs of the operator and use environment.
The propagation distance of Sub-6GHz is farther than that of millimeter wave, and it is easier to solve the signal coverage problem in a large area. Because of its wide range, better penetration of objects, and direct installation on the basis of 4G base stations, its construction cost is lower for operators.
On the other hand, the millimeter wave has higher bandwidth, which makes it easier to solve the problem of user network congestion, and at the same time to satisfy more people. This technology has a relatively small coverage area and is more suitable for applications in densely populated scenes such as stations, airports, and stadiums. The millimeter wave must achieve the same coverage level as the Sub-6GHz, and the base station density is at least 5 times that of the Sub-6GHz base station, and the cost is naturally higher.
To give a simple example, millimeter waves not only require more signal towers to cover, but also continue to output high-intensity signals. The power output of 5G base stations is three times that of 4G, and the power consumption alone is a huge expense. It is not difficult to understand that some time ago, China Unicom shut down 5G base stations at night in order to save electricity operating costs.
The cost is high and the signal coverage is easily restricted by the environment. Do American operators choose millimeter waves just because of the fast speed?
In fact, it is not. Since most of the allocatable spectrum in Sub-6GHz is occupied by the US military, there is not enough wireless spectrum to be allocated to operators. Therefore, the 5G deployment of US operators has to start with millimeter waves.
my country’s current selection of the Sub-6GHz frequency band is mainly to solve the signal coverage problem of the 5G network first, and put 5G technology into practical application as soon as possible, so that most consumers can use the 5G network. Of course, my country has also not stopped in the construction of millimeter waves.
In March of this year, the Ministry of Industry and Information Technology issued the "Notice on Promoting the Accelerated Development of 5G", and the question mentioned that "the plan for the use of some 5G millimeter wave bands will be released in due course, and the organization of millimeter wave equipment and performance testing will be organized for commercial use of 5G millimeter wave technology. Good reserves” means that the country also advocates operators to prepare for the commercial use of millimeter waves in order to facilitate future 5G construction and development.
With the characteristics of high bandwidth, low latency and high capacity of millimeter wave, in daily life, it can download Blu-ray video in seconds and solve network congestion. In particular, it can also realize remote control of industrial robots, telemedicine, etc., and its application prospects are very broad.
Write at the end
At present, many mobile phones already support 5G millimeter wave in hardware, but manufacturers will make corresponding adjustments according to the market conditions in different countries. This also answers the question at the beginning of the article. This year’s Chinese Mainland License’s iPhone 12 may not support millimeter wave, because it is not necessary for Apple and domestic operators to launch it. At this stage, consumers can’t use it at all. "True practicality" is still some distance away.
In addition, between the signal and network speed, I believe most people are more concerned about the stability of the signal. After all, the domestic Sub-6GHz 5G network speed is already very fast, and everyone does not want to experience the fear of being dominated by the iPhone signal difference.
Whether the iPhone 12 supports millimeter wave 5G or Sub-6GHz, Apple may launch an iPhone that supports different types of 5G spectrum according to the local 5G construction situation. Rather than guessing these, users may be more concerned about when the price of 5G packages can come down, which is the key to 5G popularization.
In addition, for the price of iPhone12, because of the increased cost of 5G, price increases are inevitable. However, we believe that domestic third-party e-commerce platform subsidies will be large. For example, when the iPhone 11 series was released last year, Pinduoduo immediately launched a tens of billions of subsidies, with subsidies ranging from RMB 500 to RMB 900 for the new phone. For this year’s iPhone 12 Pinduoduo will offer much discount, we might as well look forward to it.