What is satellite internet experience? In a word, in the Internet based on satellite communication, satellites are mobile "base stations". So, why use satellite to access the internet? According to data from the International Telecommunication Union, approximately one-third of the global population is still in a state of "disconnection" from the internet. Satellite Internet, which builds "base stations" in space, has wider coverage than traditional communication networks, and is an important way for people to "access the Internet" - satellite communication can provide high-speed and stable Internet services for remote areas, as well as areas that are difficult to access with traditional networks such as marine and aviation. Whether in the desert, the ocean, or on a plane, you can enjoy the same online experience as at home A few years ago, Xiang Kaiheng, who was then the chief designer of the "Hongyun Project" of China Aerospace Science and Industry Group, pointed out that satellite Internet can realize Internet access anytime and anywhere, especially in remote places where traditional mobile communications cannot reach, such as mountains, deserts, deep sea and ocean, which has more advantages. Today, the rapid development of satellite Internet has been applied in some scenarios, such as providing network connection services for vehicles, ships, aircraft and other means of transportation. For ordinary consumers, the most intuitive change brought by the satellite Internet is that when the mobile phone has no signal, it can make satellite calls. At present, many mobile phones support direct satellite communication services, which can send pictures, voice messages, and text messages through satellite networks. Some companies have also launched a paid service of "device terminal+data package" for individual users. What is the experience of browsing videos through satellite internet? A satellite Internet access package that just came into the market not long ago can provide a reference - in November this year, China Satcom launched a high orbit satellite Internet terminal and a 9GB satellite Internet access traffic package. This internet terminal can automatically connect to the satellite and complete internet operations within 2 minutes of startup. It supports up to 40M/s downstream and 6M/s upstream satellite bandwidth, enabling functions such as voice calls, short video browsing, online shopping, and video live streaming. But it's not cheap either, even after the package fee discount, it still costs 199 yuan/day. Experts pointed out that compared with ground communication networks such as 5G, the current satellite Internet network speed is not fast enough, the communication delay is relatively high, and the service cost is not low. There is still a distance to go compared to the daily internet needs of the general public. However, from the perspective of development prospects, these gaps will gradually be filled through technological progress, and in terms of user experience, there will not be much difference from ground networks in the future. Of course, the satellite Internet will not completely replace the ground network, but form a complementary relationship. In areas with good ground network signals, priority should still be given to using ground networks. Where the ground network is difficult to cover, the satellite Internet is a supplement. For example, for those who like outdoor travel and exploration, satellite Internet services are needed in the wild where mobile phone signals are not very stable. Not just complementarity. Experts pointed out that the integration of satellite Internet and ground communication network is an important development direction of mobile communication network in the future. One of the pillars of the 6G technology is satellite ground integration. With the integration of satellite Internet, 6G can become a global integrated network of space, space, space and sea. The satellite constellations have a good prospect to start building satellite Internet, but in order to achieve good signal and fast network speed, we must build a network, launch more satellites and build satellite constellations. Taking the low Earth orbit at a distance of 1000 kilometers from the Earth as an example, it takes more than 100 minutes for a satellite to orbit the Earth once. If there are enough satellites operating together in this orbit, it can achieve "no blind spots" coverage of the world. That is to say, no matter where you are or when, there will always be satellites in contact with you to ensure stable network signal coverage. A satellite constellation consists of hundreds, thousands, or even tens of thousands of satellites; The satellite orbit is mainly a low Earth orbit between 300 kilometers and 1400 kilometers from the Earth; Wide signal coverage, large communication capacity, and low signal transmission delay He Shanbao, a researcher at Beijing University of Information Technology, pointed out that personal satellite Internet should have these characteristics. According to their orbit, satellites can be divided into high orbit and low orbit. The orbit of a high Earth orbit satellite is about 36000 kilometers away from the ground, with an operating period consistent with the Earth's rotation period. It maintains a relatively "stationary" state with the ground and covers a fixed area, making it relatively easy to establish communication services. But due to the long distance, the delay and loss of signal transmission are also significant. In comparison, the low orbit satellites of hundreds to more than 1000 kilometers have the characteristics of small transmission delay and low link loss, which are more suitable for satellite Internet. At present, the United States, Britain, France, Russia, South Korea and other countries have proposed or are implementing satellite Internet networking plans. According to statistics, as of October 31, 2023, there are 52 satellite Internet constellations declared globally, including 46 near Earth orbit constellations. Among them, the most representative may be the "Star Chain" of the United States. At present, "Starlink" has launched thousands of satellites, but compared to its massive deployment plan of 42000, it can only be said to be a "big step". Our country is also accelerating its pace. In 2020, China will bring satellite Internet into the category of "new infrastructure" for the first time. In addition, the 14th Five Year Plan for the Development of the Information and Communication Industry and the 14th Five Year Plan for the National Emergency Response System have deployed the development of satellite communications and satellite Internet. In recent years, multiple satellite constellation plans have been launched successively, such as the "Hongyan" constellation of Aerospace Science and Technology, the "Rainbow Cloud Project" of Aerospace Science and Industry Corporation, the "Tianxiang" constellation of China Electronics Technology Group Corporation, and the "Tianqi" constellation of State Grid Corporation of China. According to relevant statistics, currently, China has applied to the International Telecommunication Union for 51300 low Earth orbit satellites, of which three constellation plans have a total of over 10000. China's "GW Constellation" plans to launch about 13000 satellites, and has completed the launch of technical experimental satellites into orbit; The "Thousand Sail Constellation" of Shanghai Yuanxin Satellite will create a network system of over 10000 satellites in the future, achieving global network coverage; Hongqing Technology has submitted an application for registration of the "Honghu-3" constellation to the International Telecommunication Union, and will launch 10000 satellites. It will take another ten years to deploy these massive constellations. The low Earth orbit satellite constellation is expected to become a new generation of global information infrastructure Yu Yuanhang, a senior engineer at the Beijing Institute of Aerospace Systems Engineering, pointed out. How should we respond to the constantly joining massive constellation plan in the face of seizing development space and technological breakthroughs? The challenge comes first and foremost from the increasingly scarce space resources. Under the premise of limited orbital capacity and communication frequency band, the global satellite Internet is destined to be a fierce competition. The International Telecommunication Union stipulates that the acquisition of Earth's low orbit and communication frequency resources follows the principle of "first come, first served, first served". Therefore, there is a clear "first mover advantage" in the construction of satellite constellations. At present, satellite Internet mainly relies on LEO satellites. The size of low Earth orbit space determines the number of deployable satellites. It is generally believed that low Earth orbit satellites should be located between 300 kilometers and 1400 kilometers, or between 500 kilometers and 2000 kilometers from the Earth. If the maximum value is taken, satellites can be deployed between 300 kilometers and 2000 kilometers. Roughly estimated, with a minimum safe distance of 50 kilometers between satellites in the same layer and across layers, there are only a maximum of 35 orbital shells, which can accommodate a total of 175000 satellites. However, considering issues such as spectrum allocation, a maximum of 60000 satellites can be accommodated. 60000, in the face of one grand plan after another of "ten thousand satellite constellations", seems to be struggling. The total number of low orbit satellites planned by various countries' constellation plans has already exceeded 60000. Moreover, as time goes on, the resources of the orbital frequency band decrease. Space is becoming increasingly crowded, making constellation deployment more difficult. "In order to be independent in China's communication field and consider the development channel of related industries, we need to move forward bravely, develop our own Internet constellation and seize the spectrum resources of LEO satellites." Yu Yuanhang appealed. Another challenge comes from the launch site and carrier rockets. The construction of satellite constellations brings intensive launch demands and requires more flexible and controllable satellite launch technologies. At present, there are only four launch sites in China, namely Jiuquan, Xichang, Taiyuan, and Wenchang, and the resources of these launch sites are relatively scarce. The importance of commercial space launch sites is becoming increasingly prominent, and the Hainan and Ningbo International Commercial Space Launch Sites are highly anticipated. "The construction of satellite Internet constellations in many countries is limited by the launch capacity of the launch site." He Shanbao said that the satellite Internet service requires enough satellites to be on orbit at the same time, so it requires flexible commercial launch sites or towers, and enough large-scale commercial launch vehicle mass production and development capabilities. If satellite Internet is to be affordable, the cost of constellation networking must be reduced, and the ground terminal must also be low-cost and miniaturized. As the "big head" of costs, once the cost of rocket manufacturing and launching is greatly reduced, the service fees of satellite Internet will become more acceptable. Multiple reusable launch vehicle technologies can be adopted, while also reducing costs from multiple dimensions such as the design cost, development cost, and system integration testing cost of individual rockets, "pointed out He Shanbao. The technological challenges not only come from rockets, but also from satellite ground fusion, cloud network fusion, and network security. At present, the integration of satellites and ground networks has become a focus of research on 5G enhancement technology and 6G technology. The network architecture and related key technologies of integrated satellite ground fusion urgently need breakthroughs. In addition, the integration of big data, cloud computing and satellite Internet is becoming more and more important. One of the 2024 "Top Ten Industrial Technology Issues" issued by the China Association for Science and Technology, namely, "Application of Cloud Network Integration Technology in Satellite Internet", encourages scientific and technological workers to pool their wisdom to tackle this problem. In the future, the tentacles of satellite Internet will extend to every part of our lives, and the information security and privacy problems brought by it should also be dealt with in advance. Satellite terminal trusted access, satellite encrypted transmission, anti-interference technology, etc. are also things that technology workers need to pay attention to. In January this year, the Ministry of Industry and Information Technology, the Ministry of Education, the Ministry of Science and Technology and other seven departments issued the Implementation Opinions on Promoting the Future Industrial Innovation and Development, which proposed that key technology research such as 6G and satellite Internet should be prospectively deployed. In July, the Ministry of Industry and Information Technology issued the Opinions on Innovating the Management of the Information and Communication Industry and Optimizing the Business Environment, proposing to orderly promote the reform of the satellite Internet business access system; In August, the relevant person in charge of the Ministry of Industry and Information Technology said that China would focus on integrated circuits, industrial software, satellite Internet and other fields, and make greater efforts to remedy weaknesses, forge long boards, and build new ones... The frequent initiatives made people confident in the future of satellite Internet. Of course, satellite Internet is easy to use, and it still needs to make breakthroughs in application scenarios and business models. More unique application scenarios need to be developed, such as integrated communication, navigation, and remote sensing applications, to provide satellite based information integration services for land, air, and ocean He Shanbao suggested. (New Society)