Image source @ Visual China
Text | Xinyan, author | Ye Jing, editor| Sang Mingqiang
Since the gradual scale application of 5G, there has been an endless discussion about 6G.
From the domestic research on 6G in 2018, to the pre-research of terahertz 6G at New York University and the University of California; from the establishment of the 6G Alliance, to the signing of relevant agreements between SKTelecom and Nokia and Ericsson to strengthen cooperation in 6G network research and development; in addition to Domestic, the United States, Russia, Japan and the European Union are intensively carrying out 6G research, for a time, 6G seems to be more popular than the meta-universe.
According to past experience, mobile communication technology basically maintains a "ten-year 1G" iteration cycle.
The birth of each generation of mobile communication technology is to solve the problems faced by the development of the industry, and the new generation of communication technology changes, the dimensionality reduction blow of the previous generation is often subversive. For example, the earliest 1G, which only provided a solution for mobile voice phones, such as pagers such as Big Brother; by 2G, mobile voice and SMS applications began to become popular; 3G is the era of data network communication, and the Internet application ecology has also begun to take root at this time; 4G is the golden age of mobile Internet; 5G lies in the interconnection of all things.
It may be that 3G to 4G is too silky, the arrival of 5G has not caused a wave of national replacement, and the public opinion on 6G is also polarized: positive voices think that 6G is the trend of the times; negative views think that 6G is a speculative concept, and no one really needs 6G. Of course, controversy is not the most important issue, and many people have not yet figured out what 6G is and what it will change.
From people to agents
Back in 2019, Santiago Tenorio (Vodafone's director of network architecture) said, "The industry should turn 6G into 'no-G'." In his view, the current technology has reached the top, in addition to upgrading services and applications, there is almost no room for fundamental improvement, 6G is a virtual thing. By August last year, the IEEE had conducted a survey of 6G views on hundreds of telecom network industry experts, and more than half of the people were more inclined to believe that 6G was an upgrade continuation of 5G, rather than a subversion.
Just like the widely used 4G, the data transmission rate based on the network has increased significantly, and the mobile Internet has spawned a large number of new formats, and live broadcasting is the most typical case. However, 4G can better match consumer-level application scenarios, but it is difficult to adapt to more advanced computing scenarios: such as information collection and processing in the AI field, so people's initial cognition of 5G is more at the level of faster network speed.
But in fact, 5G not only enables new concepts such as smart homes, smart wearables, telemedicine, and smart cities to be gradually realized, but also brings new business opportunities, which will change for individuals and industries.
According to the Huawei 6G White Paper, compared with previous generations of mobile communication technology, 6G will evolve from "connected things" to "connected intelligence" on the basis of 5G. Combined with the development of AI, cloud computing and big data technology, empowering everything and achieving intelligent ubiquitous connectivity, the mainstream applications of 6G will also be XR cloud services, haptic feedback, holographic display, etc.
Here we have to mention an old concept: digital twins.
In terms of use scenario, the digital twin generates a digital twin virtual world based on the physical world, and the physical world will be able to transmit information between people, people and things, things and things through the digital world. It was first used in the predictive maintenance of aircraft engines, and the "digital twin of man" is to use a large number of intelligent sensors in the human body to collect data from various organs of the real human body, and digitally reconstruct it to form a digital person.
Figure: 6G scene (Source: China Mobile Research Institute)
In some of the assumptions of 6G, in the future, people can transmit touch, smell, taste, and even human emotions can be transmitted and interacted, of course, the science fiction color in this context is too strong, so some people think that 6G is unnecessary.
Technical principles of 6G
Next, let's talk about the technical aspects of 6G.
As we all know, from 1G to 5G, in order to improve the speed and capacity of wireless links, mobile communications always expand towards more spectrum and higher frequency bands. According to the Nikkei Shimbun, Japan's current 5G communications are dominated by frequency bands below 6GHZ, and the speed and 4G are not much different. The reason why the 6G technology offensive and defensive war was launched early was to cope with the future competition in the use of terahertz and artificial satellite technology.
Add a knowledge point: terahertz is a frequency unit, 1THz = 1000GH, based on terahertz technology, 6G network speed can reach more than 50 times the 5G network speed, that is, in the 6G era, the indoor accuracy error may be reduced to less than 10 cm, and the error in outdoor accuracy will not exceed 1 meter.
As a communication carrier of high-speed broadband, terahertz waves have extremely high directionality and penetration capabilities, so they are suitable for short-distance confidential communication in harsh environments and are also suitable for satellite communications with high bandwidth requirements. The International Communications Union believes that if 6G is to become an ultra-high-speed network based on terahertz technology, it needs to open up the frequency band range of 100GHz-10THz.
Because the previous mobile phone communication network is mainly based on the base station connected by optical fiber to access the Internet, because the application scenario of 6G will be more abundant, considering the difficulties of building ground base stations such as near-air and sea surface, mountains, deserts, etc., low-orbit satellites and high-altitude pseudo-satellite drones flying in the stratosphere will be used, satellite communication will be an important supplement to the traditional ground mobile communication system, and the coverage of air-space integration has become a trend.
Some industry experts believe that unlike the current mobile phone communication network, which is based on a base station connected by optical fiber, "the 6G network will realize the connection between terrestrial wireless and satellite communications." "In this way, the network signal arrives seamlessly, ideally covering all corners of the world, even allowing people in remote areas to receive telemedicine and education, and, under the linkage of satellite systems and ground networks, more accurate weather forecasting can be carried out to quickly respond to sudden natural disasters."
But it has to be said that for terahertz technology, we still need to be rational.
In general, the iteration of the network is divided into two levels, one is transmission, and the other is application. Transmission refers to the hardware level, such as base stations, chips, etc., and applications mainly refer to software. Because 4G has been implemented into specific software applications, so it can change our way of life to a certain extent, the success of 4G has made the pressure on 5G and 6G increase sharply, so we can often hear: Although everyone talks about 5G every day, 5G is only mature in the hardware dimension, and there is still a long way to go from the actual scale application, as for 6G, it still stays in the theoretical aspect.
Wenku (vice chairman of the China Communications Standardization Association) once said, "Terahertz as an important technical direction of 6G, the premise is to first cultivate millimeter wave maturity." "The reason behind this is very simple, and now the millimeter wave used for 4G and 5G still has problems such as weak coverage capability, high network construction costs, and immature terminal ecology that need to be solved urgently."
In other words, even in the 6G era, terahertz waves may encounter similar problems. If MassiveMIMO (large-scale antenna technology) is the iconic technology of 5G, then the main direction of 6G is how to improve scene adaptability, reduce system overhead, simplify computing, and improve multi-user pairing efficiency.
People often think that AI has opened a window to 5G, 5G can make AI more ubiquitous, and the "Internet of Everything" is proposed on this basis. Then the question is, who will knock on the door of 6G demand, whether the "intelligent connection of all things" is a true proposition or a false proposition, these questions must wait until the 6G standard comes out to answer.
How far is 6G from us?
The change of communication technology is no more than others, in general, there are standards before there are applications.
However, it should be noted that standards often come from direct feedback from scene-scale applications, and 6G is no exception, rather than saying that the industry is competing for 6G technology, it is better to find a real test field for the standard. At present, although the industry has not yet formulated a unified standard for 6G, but the process of 6G commercialization has reached a preliminary consensus, and planned a prototype of the timeline, last year's science and technology list conference, Wang Jianzhou (the former chairman of China Mobile) said, "By 2030, 6G will be commercial." ”
At a time when 5G has not yet been fully popularized, many people complain that 6G is destined to "get up early and catch up with a late set", but with reference to the development law of the mobile communication industry "with a generation, a generation, and a generation", it is not too much to prepare for the next generation of communication technology in advance and carry out forward-looking research and development and patent reserves.
After all, rising to the strategic level is likely to be the key to seizing the commanding heights of the future information industry.
According to Liu Guangyi (chief expert of China Mobile Research Institute), based on the 5G research and development process, the entire 6G research and development will be roughly divided into two stages. The first phase (2018-2025) is the research verification of vision, requirements definition and key technologies, system concept design and prototype verification; the second phase (2026-2030), 3GPP begins the research and development of relevant standards, "end-to-end" industrialization promotion, business and application cultivation and commercial deployment.
Looking abroad, Finland took the lead in releasing the world's first 6G white paper, Horizon2020 organization launched the "intelligent network and services" 6G research project, the United States has always attached importance to terahertz and the field of air-space integration technology, forming a low-orbit satellite Internet formation with SpaceX, Amazon, Astra and Boeing as the core members; Japan and South Korea 6G research bias towards school-enterprise cooperation, of which LG, Samsung established a 6G research center, and released a 6G white paper. The content covers the 6G vision, evolution trends, application scenarios, standardization timelines, etc.
When we compare the development needs of communication networks with Maslow's hierarchy of needs theory, it is not difficult to find that the latter starts from the perspective of human motivation, dividing human needs from low to high into physiology, security, social, respect and self-realization, the former from 1G development to the present, from basically meeting the communication needs between people, to meeting the needs of various life scenarios, and then to the high-speed connection between people and things, things and things, communication technology has become a link connecting the real physical world and the virtual digital world.
But the failure of Moore's Law inevitably makes us stop and think: Is it too early to talk about 6G?