The 700Mhz frequency band has the characteristics of wide coverage, strong penetration, and low networking cost, so it is also called the golden frequency band. Recently, the results of the much-anticipated centralized procurement of 5G 700M base stations and antenna products between China Mobile and China Radio and Television were officially released. At this point, the curtain of large-scale construction of 5G 700M in my country has officially begun.
In China, no frequency band attracts as much attention as 700Mhz. According to the plan of China Mobile and China Radio and Television to build a shared 5G network, China Radio and Television will complete the deployment of 400,000 700MHz stations with China Mobile in 2021; in the first half of 2022, it is planned to open 480,000 stations and fully support 5G Broadcasting business; full network coverage will be achieved within two years. However, in addition to frequency clearance work, 5G 700MHz also faces many challenges in terms of technology and coverage.
Frequency clearing needs to be accelerated
The 700MHz frequency band specified in the 3GPP standard was originally a broadcast and television band. Therefore, 700MHz migration is an important basic condition for the construction and operation of 5G networks.
For the construction of 5G 700MHz network, China Radio and Television has also officially launched frequency clearance work. On July 5, following the failure of the first bidding, China Radio and Television launched the national terrestrial digital TV 700MHz frequency migration project general contracting (EPC) (second) bidding. This bidding project involves a total of 6,026 stations, involving There are 12,350 channels, and the budget is still 1.8 billion yuan. The results of the second frequency clearing bidding are planned to be announced on July 26.
Frequency clearing is a heavy workload and difficult. Some high-power broadcast towers still occupy important frequency resources. Frequency clearing work will inevitably bring about major changes in terrestrial analog and terrestrial digital transmitters. Undoubtedly, the previous 700 MHz frequency migration project failed due to less than 3 valid bidders, which to some extent illustrates the complexity of the 700 MHz frequency clearing work.
In May this year, during the 2021 China International Radio and Television Information Network Exhibition, Song Qizhu, Chairman of China Radio and Television, pointed out that China Radio and Television had signed a *** construction and sharing agreement with China Mobile and formulated two The construction plan to achieve full network coverage within the year has been completed, and equipment selection and technical testing have been completed. The construction of the radio and television 5G 700MHz network is being promoted as planned. At the same time, the "side construction and side operation" plan is refined and improved, and Section 192 will be implemented in an orderly manner. Numbers are released nationwide for commercial use.
Relevant people in the radio and television industry have pointed out that with the help of China Mobile's rich network construction experience, once network construction begins, both parties only need to proceed according to the plan and will not encounter too many difficulties. What affects the final commercialization time of the 700MHz network is the frequency migration work of radio and television itself. The 700M frequency clearing will realize the business migration of terrestrial analog TV and terrestrial digital TV broadcasting in the 700M frequency band.
It is worth noting that the "5G Application "Sail" Action Plan (2021-2023)" recently clearly stated that 5G frequency resource guarantees should be strengthened. Continue to do a good job in coordinating interference from radio stations such as 5G base stations and satellite earth stations. Promote the frequency migration of radio and television services in the 700MHz band and accelerate the deployment of 5G networks in the 700MHz band.
Therefore, for radio, television and mobile, digital broadcasts are still being sent on some frequency bands of 700MHz, and the frequency cannot be cleared in a short time. Therefore, the deployment of 700MHz NR still needs to be considered with broadcasting Intersystem interference between large towers.
The capacity problem is highlighted
As we all know, the higher the 5G frequency, the higher the peak rate it can provide, but in contrast, the coverage effect will be worse. Therefore, 700MHz The coverage capability is extremely excellent. Its coverage radius is about 3-4 times that of the 2.6GHz frequency band, and its coverage area is 10 times that of the 2.6GHz frequency band. According to reports, using the 700M frequency band only requires the construction of 450,000 to 500,000 base stations. 5G network covers the whole country.
However, due to the low frequency of 700M, the wavelength is relatively large. As a result, when transmitting or receiving signals, the size of the antenna element required must also be correspondingly larger. Moreover, in the available bandwidth, 700M The available bandwidth is much smaller than that of 2.6GHz and 3.5GHz, which makes the problem of insufficient capacity even more serious.
In this regard, in April last year, the Ministry of Industry and Information Technology officially issued the "Notice on Adjusting the Frequency Usage Plan of the 700MHz Band" to use the 703-743MHz and 758-798MHz frequency bands for FDD (frequency division duplex) In the 5G communication system, the uplink and downlink each have a bandwidth of 40MHz, and they communicate simultaneously in both directions without interfering with each other. This improves the system capacity of the 5G network and the coverage of a single base station. For this reason, in actual use, operators use 5G Combining the advantages of the TDD system, 2.6G or 3.5G carriers focus on downlink capacity. While 700M supplements the downlink capacity, it also focuses on uplink coverage and optimizes the shortcomings of insufficient bandwidth of 700M.
In terms of the number of base stations constructed, 700MHz NR has the characteristics of short construction period and huge construction quantity in China. It needs to complete the construction of 480,000 stations in a short time. It has advantages in terms of construction rhythm and supply speed. Higher requirements.
In this regard, some experts suggest that in the initial stage of 700MHz NR network construction, a different network roaming solution should be adopted, which only needs to connect the core networks of China Mobile and China Radio and Television. In the second stage, after 700MHz NR large-scale networking, an access network sharing solution will be adopted. China Mobile will build a separate transmission network and access China Mobile and China Radio and Television core network nodes respectively.
In terms of equipment, although the 700MHz industry chain has accumulated rich experience in the 4G era, most of the 700MHz NR networks that have been commercialized abroad have 2*10M and 2*20M bandwidth, and are mainly 2T2R and 2T4R equipment. , while domestic 5G 700MHz uses 2*30MHz large bandwidth as the deployment standard and 4T4R as the product standard. Innovations in product technology also pose new challenges to equipment manufacturers.
Take CITIC Mobile as an example. CITIC Mobile uses business channel wireless detection technology combined with flexible configuration of control channel resources to ensure site performance, speed up the pace of 700M construction, reduce the number of sites required, and ensure the application of 700M site construction. It can be opened as much as possible, and the frequency domain positions of the uplink and downlink public control channels can be flexibly configured to ensure that users can access the 700M network normally.
Industry experts also pointed out that if 700MHz can obtain larger bandwidth for deploying 5G, it will better achieve low-cost and wide coverage of 700MHz NR.
Give full play to the effectiveness of the "golden frequency band" to accelerate application empowerment
As a leading technology in the field of new generation information and communication technology, 5G is a key new infrastructure that empowers the digital economy. In the past two years of commercial use, the number of 5G base stations in my country has exceeded 900,000, and the number of 5G terminal connections has exceeded 330 million. It has accelerated from network construction to a new stage of application innovation.
Coverage is not the purpose, application is the core. Obviously, the iterative development of technology is to better support the industry. It needs to be based on the actual needs of the industry, based on reality, industry needs and public needs, iterative development of 5G technology, and the realization of the Internet of Everything. And 700MHz will play a huge role in network traffic migration, 5G user experience improvement, and empowering thousands of industries.
"The deployment of 700MHz will quickly cooperate with 2.6GHz to form a large-scale continuous coverage this year. The expansion of the coverage area will be conducive to 5G empowering thousands of industries." Regarding the ** of China Mobile and China Radio and Television * Construction and sharing, Deng Hongwei, President of CITIC Mobile Operator Network Product Line, pointed out that the construction and sharing of the 700MHz high-quality frequency band will help the golden frequency band play its maximum role and benefit China Mobile and China Radio and Television The launch of high-quality 5G services by operators can effectively assist the construction of the 5G industry and promote the rapid development of 5G services, which are blooming everywhere. The implementation of China Mobile and China Radio and Television's first-class construction sharing can achieve a win-win situation.
At present, my country's 5G development has entered a "no man's land". There is no mature experience in technology, industry, and application to draw from internationally. It will definitely go through an innovation process of overcoming difficulties. Obviously, as China's 5G As the scale of network construction deepens, the demand for 5G base stations continues to rise. Under the influence of cost effects, equipment manufacturers’ base station manufacturing costs continue to decrease, achieving a win-win situation for operators and equipment manufacturers. By then, as a channel that connects everything in society, how to make 5G a channel that connects everything in society? A "channel" that maximizes its value capabilities will also lead to continued exploration by all parties in the industry chain, forming a favorable situation for the accelerated development of digital transformation and upgrading in various industries.