Among the nouns such as 3G, 4G and 5G, G is the abbreviation of the English word "Generation X". Therefore, 5G is the fifth generation mobile communication technology.
First, the key points of the development process of 5G
In the field of mobile communication:
The first generation is imitation skills; The second generation completed digital voice communication; The third generation is a well-known 3g skill, characterized by multimedia communication. The fourth generation is the popularization of 4g technology, and the communication rate has greatly increased, marking the entry into the era of wireless broadband.
In short, the speed of 5G will be faster than that of 4G, and the power consumption will be lower, which will bring a series of new wireless products. Li Zhengmao, vice president of China Mobile, once made a speech, demanding a sharp price reduction of telecom equipment in the 5G era: "From 4G to 5G era, the transmission cost per bit has dropped by 1 1,000 times, so we also expect the price of telecom equipment to drop by 1 1,000 times. Cost is the key to determining whether operators can make profits in the data age. "
5G is not a brand new technology.
Two different concepts about 5G:
There is a concept that 5G will be a brand-new skill. The representative of this concept is CMO Yang Chaobin of Huawei's wireless network product line. In his view, no matter how 4G evolves, it will not become 5G, and 5G will be a brand-new skill.
5G is not only a skill update, but also a great leap forward and an innovation, which also means that the network architecture needs to be improved, and the network demand of 5G will be completely different from that of 4G; Although the 4G LTE skills used today will continue to evolve, no matter how 4G evolves, it will not become 5G, and 5G will be a brand-new skill.
But most skill experts prefer the following concept: 5G is the inevitable evolution of 4G skills-both evolution and revolution.
Although the skills of any generation are not necessarily the repetition of the skills of the previous generation, if the skills of the new generation are the same as those of the previous generation, there will be no new generation, so the skills of 3G are different from those of 2G, and the skills of 4G and 3G are different. Their skill principles, problem-solving methods, arrangement methods and talents are different, but there is no skill foundation of the previous generation. Perhaps the next generation has not inherited the skills of the previous generation, and it is a mirage to complete the revolutionary promotion.
5G is not an amazing new skill. 5G skill is a new combination of existing skills and a re-evolution of 4G skill.
Why should we focus on "once again"? Since the last three letters of 4G LTE represent long-term evolution, 5G should be a re-evolution on the basis of 4G. Regarding the concept of skill evolution, Occam's razor, a member of the Scientific Squirrel Society, has a simple bimodal theory, which can clearly explain that 5G is just a concept of skill evolution.
The bimodal theory of Occam's razor:
Occam Razor believes that after a new skill concept is put forward, there will be a discussion climax in the industry, which is the first hump.
Related academic papers will become hot spots, and piles of doctoral and master's degrees will be completed based on this new skill. Although enthusiastic, it is only limited to academic discussion, and there are still many questions about the completion of detailed skills, which may not be mass-produced for financial reasons.
The climax of the discussion gradually cooled down, which was the first hump decline period, followed by in-depth and pragmatic skills research. This passage period may be several years, or it may be more than ten or twenty years. When the skill problems are handled well, it will usher in the upsurge of mass production into the market, which is the second hump.
According to the plan of the World Telecommunication Union in 2020, all of them will enter 5G in five years, but so far, the central skill system has not been established. Looking back on the development history of 3G skills, the World Telecommunication Union accepted the proposal of 3G skills on1June 30th, 998, and ushered in the first hump period. It was not until June 7, 2009 that the Ministry of Industry and Information Technology officially issued three 3G licenses before entering the second hump. The passage period is as long as 1 1 year, especially three license plates. According to the "double hump rule", the skills applied in the world five years later should have the first hump at the mercy of 20 10, which will not be born in the first two or three years of 2020, and then Agile will be determined as the global 5G specification by the World Telecommunication Union, which violates the usual law of skill development and is unlikely to come true.
Without 3G and 4G skills, there would be no 5G.
In essence, most R&D institutions in the 5G discussion are the same, walking on two legs.
In the development of 5G, it is proposed to walk on two legs: on the one hand, continue to promote the evolution of 4G skills, on the other hand, develop new 5G skills, and the two are coordinated.
Faced with the requirement of a thousand times speed-up in the 5G era, it is only possible to greatly increase the bandwidth after the evolution of 4G skills. Increasing bandwidth is the starting point, followed by millimeter wave, micro-base station, high-order MIMO, beamforming and so on. Are natural skill trends. In the 5G era, key skill centers such as large antenna array, millimeter wave skills, new network architecture and new air interface planning are mostly based on the extension of 4G network skills, and most of them can improve their functions exponentially. Take soft air interface skills as an example. This skill is connected with the hardware processing ability of Pre5G, which enables operators to smoothly upgrade from 4G to 5G. During the period from 4G to Pre5G, there is no need to change the terminal, but from Pre5G to 5G, the base station equipment can continue to be used.
Micro-base station under millimeter wave technology
Understanding that 5G is the fundamental definition of the fifth-generation mobile communication skills means that it is upgraded from 3G and 4G, and it is also a skill accumulation and evolution. It can also be said that without the development of 3G and 4G skills, there would be no 5G. On the one hand, the evolution of 5G skills is the inevitable result of skill accumulation, and of course it also needs revolutionary and innovative policies to complete the evolution. On the other hand, it is also the inevitable requirement of the rapid progress of human communication needs.
On the other hand, before the 5G delay, first, the skills were not reached, and second, the unused requirements were presented. Now there is demand for 5 G, what demand? The future network will face: 1000 data capacity addition, 10 to 100 wireless device connection, 10 to 100 user rate demand, 10 battery life demand and so on. Frankly speaking, perhaps in the next five or six years, 4G networks may not be able to meet these needs, so it is necessary for 5G to come to power in advance.
Judging from the evolution of skills, and recalling the hard struggle in 3G and 4G times in China, we have reason to believe that the progress of industry and skills in China has also laid a solid foundation for 5G planning. China has changed from being forced to undertake skills in the past to exporting skills, and will have the opportunity to develop into one of the first countries in the world in terms of 5G skills, specifications, industries and application services. From following to leading, China's communication industry has the opportunity to learn from China's high-speed rail, and complete the curve overtaking in the 5G era. China enterprises such as Huawei, Datang and ZTE, the three major operators, have long invested in the development of 5G, leading the world.
2. What are the advantages of 5G?
For several consumers, the value of 5G is that it is faster than 4g LTE (the peak rate can reach tens of Gbps). For example, you can download a high-definition movie in one second, while 4G LTE may take 10 minutes. It is precisely because of this unique advantage that the industry generally believes that 5G will play an important role in the fields of driverless cars, VR and Internet of Things.
Compared with 4G, the progress of 5G is all-round. According to the definition of 3GPP, 5G has the characteristics of high function, low delay and high capacity, and these advantages are mainly embodied in the five skills of millimeter wave, small base station, large-scale MIMO, full duplex and beamforming.
1, millimeter wave
As we all know, with the increase in the number of devices connected to wireless networks, the problem of scarce spectrum capital has become increasingly prominent. At least at present, we can only enjoy limited bandwidth in a very narrow spectrum, which greatly affects the user experience.
So how to complete the peak speed of tens of Gbps provided by 5G?
As we all know, wireless transmission usually has two ways to improve the transmission rate, one is to improve the spectrum utilization rate, and the other is to improve the spectrum bandwidth. Using millimeter wave (26.5-300GHz) in 5G is the second way to improve the speed. Taking the 28GHz band as an example, its available spectrum bandwidth reaches 1GHz, while the available signal bandwidth of each channel in the 60GHz band is 2GHz.
In the history of mobile communication, this is the first time to open up new frequency band capital. Before that, millimeter wave was only used in satellite and radar systems, but now operators have begun to use millimeter wave for testing between base stations.
Of course, the biggest defect of millimeter wave is its poor penetration and large attenuation, so it is not easy to transmit 5G communication in millimeter wave band in high-rise buildings. Small base stations will deal with this problem.
2. Small base station
As mentioned above, millimeter wave has poor penetration and great attenuation in the air, but because of its high frequency and short wave length, it means that its antenna scale can be made very small, which is the basis for arranging small base stations.
It is foreseeable that in the future, 5G mobile communication will no longer rely on the deployment architecture of large base stations, and many small base stations will become a new trend, which can cover up the peripheral communication that large base stations can't reach.
Due to the dramatic reduction in size, we can set up a small base station around 250 meters, so that operators can set up thousands of small base stations in each city to form a dense network, and each base station can receive signals from other base stations and send data to users in any direction. Of course, you don't have to worry about power consumption. Small base stations are not only much smaller than large base stations, but also greatly reduce power consumption.
In addition to millimeter-wave broadcasting, 5G base stations will have many more antennas than today's cellular network base stations, that is, massive MIMO skills.
3, large-scale MIMO
The existing 4G base station only needs a dozen antennas, while the 5G base station can support hundreds of antennas. These antennas can form a large-scale antenna array through massive MIMO skills, which means that the base stations can send and receive more users' signals together, thus increasing the capacity of the mobile network by dozens or even more.
MIMO (Multiple Input Multiple Output) refers to multiple input multiple output. In fact, this technique has been used in some 4G base stations. But so far, Massive MIMO has only been tested in the laboratory and several field experiments.
Ove Edfordors, a professor at Lund University, once pointed out that "Massive MIMO has opened up a new direction of wireless communication-when the traditional system uses time domain or frequency domain to enjoy capital among different users, Massive MIMO has introduced a spatial mode, that is, many antennas are selected at the base station and synchronized, so that we can get dozens of times of spectrum efficiency and power gain together."
There is no doubt that Massive MIMO is the key skill of 5G commercialization, but multiple antennas will inevitably bring more interference, and beamforming is the key to deal with this problem.
4. Beamforming
The primary challenge of Massive MIMO is to reduce interference, but it is precisely because of the skills of Massive MIMO that more antennas are integrated into each antenna array. If these antennas can be effectively manipulated to cancel or enhance the space of each electromagnetic wave announced by them, a very narrow beam can be beamed instead of transmitted in all directions, and the limited energy will be concentrated in a specific direction for transmission, which not only makes the transmission interval farther, but also prevents signal interference.
The advantage of this skill is not only that, it can improve the spectrum utilization, and we can send more information from multiple antennas together through this skill; In the large-scale antenna base station, we can even calculate the best way of signal transmission through the signal processing algorithm, and finally get the position of the mobile terminal. Therefore, beamforming can deal with the problem that millimeter wave signals are blocked by obstacles and attenuated in a long distance.
In addition, let's finally talk about another major feature of 5G-full duplex skills.
5, full duplex
Full duplex skill means that the transmitter and receiver of the equipment work together with the same frequency capital, so that both ends of communication can use the same frequency at the same time, which breaks through the existing forms of frequency division duplex (FDD) and time division duplex (TDD). This is one of the keys for communication nodes to complete two-way communication, and it is also the key skill of high throughput and low delay required by 5G.
Receiving and transmitting together on the same channel undoubtedly greatly improves the spectrum power. However, to use this subversive skill, 5G also faces a lot of challenges. According to the materials published before mobile communication, there are three major challenges:
In the planning of circuit board components, ADRC should meet the requirements of broadband (greater than 100MHZ) and multiple MIMO (above 32 antennas), requiring small scale, low power consumption and not too high cost. Optimal planning of physical layer and MAC layer, such as coding, modulation, synchronization, inspection, interception, anti-collision, ACK, etc. Especially for the physical layer optimization of MIMO. Control plane optimization of dynamic switching between full-duplex and half-duplex, and optimization of existing frame structure and control signaling.
Therefore, although the momentum of 5G far exceeds the previous 4G, the future of 5G is still full of uncertainty. Now we need to wait for these skills to become useful from the probation period.