5G frequency band: Expansion millimeter wave

5G frequency band: Expansion millimeter wave

5G frequency band, Recently, a well-known Apple analyst issued a report saying that in 2020, Apple will release 5 new iPhones that support millimeter-wave/sub-6GHz technology, bringing a small surprise to a group of people who are concerned about 5G millimeter-wave applications.

The International Organization for Standardization 3GPP divides the 5G frequency band into the FR1 frequency band and the FR2 frequency band. The FR1 frequency band is a sub-6GHz frequency band ranging from 450MHz to 6GHz, and the FR2 frequency band is a millimeter-wave frequency band ranging from 24.25GHz to 52.6GHz. Therefore, there are only two frequency bands for global 5G deployment, sub-6GHz, and millimeter-wave.

Regardless of whether Apple can make predictions a reality, the commercial prospects of 5G for millimeter-wave spectrum resource mining are increasingly popular. At the 2019 World Radiocommunication Conference (WRC-19 Conference), John Giusti, Chief Regulatory Officer of the Global System for Mobile Communications Association (GSMA), wrote an article on the prospects of 5G millimeter wave business: "From 2020 to 2034, in In 15 years, the utilization of millimeter-wave spectrum resources is expected to drive global GDP growth of US$565 billion.

Millimeter-wave is favored by 5G

The propagation of wireless signals exists in the form of radio waves, just like a vehicle must drive on the road. All radio services are inseparable from radio frequency, which is measured in Hz (Hertz). If each Hz radio wave is a key, the piano keys are all radio frequencies, and the entire radio frequency spectrum is divided into 9 segments (frequency bands), which have different application spaces.

As stated by Wang Zhiqin, vice president of China Academy of Information and Communications Technology, the frequency spectrum is the basis for the development of wireless mobile communication technology. Counting from the radio communication experiment conducted by the Italian Marconi and the Russian Popov in 1895, the spectrum has been known, developed, and used for more than a hundred years. In this process of conquering more frequency bands to obtain greater bandwidth, The emergence of 5G has finally made millimeter waves a sweet potato.

Millimeter waves refer to electromagnetic waves between 1 and 10 millimeters, usually corresponding to the radio frequency spectrum between 30 GHz and 300 GHz. At present, millimeter waves are mainly used in satellite communications, radar, and military fields.

In addition to the spectrum resources within 30GHz that have been divided up by operators and various institutions, the reason for 5G to use millimeter waves is very simple, because this part of the spectrum has continuously available ultra-large bandwidth, which can meet the needs of 5G for ultra-large capacity and extremely high Rate of transmission requirements.

However, the higher the frequency of electromagnetic waves, the shorter the propagation distance. The extremely high-frequency millimeter waves have a large path loss when they propagate. Not only is it difficult to pass through buildings or obstacles, but even a leaf or a drop of rain may cause damage. It absorbs.

Meng Pu, Qualcomm chairman, said: “5G will use almost all available frequencies in the world, including millimeter waves, and there will be many new technical challenges in every stage of 5G development. For example, 5G radio frequency will have more than 10,000 A possible combination of frequency bands, this complexity is an order of magnitude higher than in the 4G era."

Moreover, with the improvement of new materials, new technologies, and new processes, the constraints of the large-scale application of millimeter waves in the 5G era will also be gradually resolved.

The battle for spectrum focus continues

The spectrum resources available in the mid-to-low frequency band (below 6GHz) are difficult to release, and the millimeter-wave frequency band has become a new hope for supporting and guaranteeing 5G applications. The International Telecommunication Union (ITU) focused on 11 candidate frequency bands in the range of 24.25GHz-86GHz for the 1.13 topic specially set up by the WRC-19 conference held not long ago, looking for new 5G frequency band.

The important tasks of the 1.13 topic also include, on the basis of carrying out compatibility studies, amending relevant international regulations or formulating protective measures to avoid 5G services and satellite communications that have used this frequency range, earth resources, and climate change monitoring, and radio astronomy. Interference in business, seek harmonious coexistence.

The main person in charge of the 5G millimeter wave issue of the Chinese delegation, Dr. Wang Tan from the National Radio Monitoring Center, emphasized that the results of the above two tasks will have a profound impact on the information and communication technology industry. Therefore, the 5G millimeter wave issue has become the WRC-19 conference for all countries in the world and The main battlefield of international organizations.

Although at this conference, the 26GHz 5g frequency band (24.25GHz-27.5GHz), the 40GHz 5g frequency band (37GHz-43.5GHz), and the 66GHz-71GHz frequency band are all or partly identified as the globally unified 5G frequency bands, there are disputes about the conditions of use of these three frequency bands. Not closed.

For example, the 26GHz 5g frequency band that the global 5G industry is striving for has the advantages of low frequency, large bandwidth, and relatively small equipment implementation. However, this frequency band is adjacent to the satellite earth exploration business, and a globally unified 5G base station out-of-band useless radiofrequency limit has been formulated. , Is an important technical means to reduce the possibility of interference in 5G systems.

The smaller the limit value, the stricter the technical indicators, which means that the higher the equipment R&D investment and networking cost, the higher the frequency protection will be. The looser the limit value, the more potential interference will be caused to adjacent frequency meteorological services. Whether the out-of-band radiofrequency limit is wide or strict is not only related to the trade-off between industrial interests and human observation but also related to the strategic layout of countries.

The 40GHz 5g frequency band, which is subdivided into 3 continuous frequency bands, is distributed with various satellite services, positioning services, radio astronomy, space research, and other radio services. The point of contention is whether to use all three frequency bands for 5G or to clarify only one of them. China hopes that space and terrestrial industries will develop in a balanced manner, and part of it will be used for 5G. It believes that giving space to the satellite industry is as important as protecting other radio services.

Commercial deployment has yet to mature

The timely release of the 5G millimeter-wave frequency band frequency usage plan is the key to guiding the development of the 5G millimeter wave industry. According to the prediction of Guan Zhou, General Manager of Public Policy for the Greater China Region of the Global System for Mobile Communications Association (GSMA), the 5G millimeter-wave frequency band will fall, and the Ministry of Industry and Information Technology will soon start millimeter-wave plans in China.

As an important support for China’s millimeter-wave planning, my country’s IMT-2020 (5G) Promotion Group (hereinafter referred to as the Promotion Group) organized China’s 5G enhancement technology research and development test millimeter-wave frequency band test trials, the global industry chain of systems, chips, Major companies such as instrumentation have different degrees of participation. Xu Fei, leader of the 5G test working group of the promotion group and deputy chief engineer of the Institute of Technology and Standards of the China Academy of Information and Communications Technology, said that the test progress was much earlier than expected.

So, when will 5G millimeter waves be commercially available in my country?

The test plan of the promotion group draws a rough timeline: August-December 2019, to verify 5G millimeter wave key technologies and system characteristics; in 2020, plan to verify the functions, performance, and operation of millimeter-wave base stations and terminals, and develop high and low frequencies Collaborative networking verification; 2020-2021, plans to carry out typical scenarios verification.

From the perspective of operators, experts of China Mobile Research Institute, revealed at the 2019 5G Millimeter Wave Technology Innovation Seminar that China Mobile has completed 5G millimeter wave key technology verification and plans to gradually commercialize 5G millimeter wave in 2022.

Obviously, China's 5G millimeter wave plan is not as radical as the United States.

The United States uses millimeter waves in 5G trials and commercial deployment. Liu Yunjie, an academician of the Chinese Academy of Engineering, once analyzed that the key reason is that all 5g frequency band below 6GHz in the United States are used by the military.

Contrary to the United States, China is not in a spectrum "dilemma". The use of spectrum in the 3GHz and 4GHz frequency bands and the 5G systems and terminal equipment in the frequency bands below 6GHz are leading the world, providing a guarantee for the early large-scale and rapid deployment of 5G.

The typical use scenario of the millimeter-wave is self-backhauling, and no fiber link is required. From the perspective of network infrastructure, the optical fiber coverage in the United States and parts of Europe is far lower than that in China, and the use of microwave technology for backhaul is an economically feasible solution

Therefore, when the 5G millimeter wave industry chain is not yet mature, China's current 5G deployment strategy is a more mature choice. As Minister of Industry and Information Technology emphasized: “Respect market laws and promote the gradual development of 5G applications. 5G applications involve many emerging fields, and we need to continue to explore and summarize, and adopt the strategy lay eggs along the way' in the process of cultivation. 5G applications continue to land.