Is the integrated air-space-ground information network really coming?

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In recent years, with the popularization and development of the Internet and the Internet of Things, as well as the increasing demand for airborne, shipborne, and space relay communications, satellite Internet and 5G networks have begun to integrate and develop, gradually entering the era of "global broadband Internet". 5G "air-space-ground integration" will become an important development trend of future information networks. The "China Unicom Air-Space-Ground Integrated Communication Network White Paper" points out that "large low-orbit satellite constellations are an important development trend of current satellite communication systems" and "air-space-ground integrated communication networks are an important development trend of future 6G networks and are currently in the early stages of development." Therefore, promoting the mature implementation of satellite Internet and accelerating the integration of satellite Internet and 5G networks have become key milestones in building an air-space-ground integrated information network.

1. my country's policy layout

In April 2020, the National Development and Reform Commission held a routine press conference and clarified the scope of new infrastructure for the first time. Satellite Internet was included in the scope of communication network infrastructure. In May of the same year, the National Development and Reform Commission mentioned in the "Report on the Implementation of the 2019 National Economic and Social Development Plan and the Draft of the 2020 National Economic and Social Development Plan" that it would promote the in-depth application of 5G, support the development of commercial aerospace, extend the aerospace industry chain, and expand satellite applications such as communications, navigation, and remote sensing. On April 29, 2021, the State-owned Assets Supervision and Administration Commission of the State Council issued a document to establish China Satellite Network Group Co., Ltd., which aims to plan and develop space Internet satellites and launched experimental satellites; the country will also establish a "State Grid" company specifically responsible for coordinating the planning and operation of space Internet construction.

After the national policy was introduced, various regions also successively laid out the satellite Internet industry chain. In May 2020, the Shanghai Municipal Government took the lead in issuing the "Shanghai Action Plan for Promoting New Infrastructure Construction (2020-2022)", and satellite Internet infrastructure construction was included in the action plan. In June, the Beijing Municipal Government issued the "Beijing Action Plan for Accelerating New Infrastructure Construction (2020-2022)", proposing to "promote satellite Internet technology innovation, ecological construction, operation services, application development, etc., and promote the coordinated development of central enterprises and Beijing's innovative enterprises". In the same month, the Chongqing Municipal Government issued the "Chongqing New Infrastructure Major Project Construction Action Plan (2020-2022)", proposing to "speed up the planning of global low-orbit satellite mobile communications and space Internet construction, and build a national space Internet headquarters base and a low-orbit Internet small satellite constellation application demonstration base". In July of the same year, the Zhejiang Provincial Government issued the "Three-Year Action Plan for New Infrastructure Construction in Zhejiang Province", proposing to focus on core areas such as 5G networks and satellite space-time information service facilities to build a new generation of digital infrastructure networks.

2. my country’s practical exploration

Since 2017, international standardization organizations such as the International Telecommunication Union (ITU), the Third Generation Partnership Project (3GPP), and the 5G Satellite and Terrestrial Network (SaT5G) Alliance have begun to study the integration of satellite Internet and 5G. At the 2019 European Network and Communications Conference (EuCNC2019), the SaT5G Alliance announced the successful demonstration of a series of satellite 5G demonstrations. In recent years, my country has also made many explorations in promoting the integration of air, space and land.

In terms of low-orbit Internet constellations, the "Hongyan Constellation" designed by China Aerospace Science and Technology Corporation is composed of 54 mobile satellites and 270 broadband satellites. The "Hongyun Project" proposed by China Aerospace Science and Industry Corporation plans to launch 156 satellites to build my country's first low-orbit Ka broadband communication constellation system with global coverage. Galaxy Aerospace Company plans to complete the construction of a 144-satellite constellation with an orbital altitude of 1,156 km by 2023.

In terms of low-orbit IoT constellations, CASIC, Jiutian Microstar, Guodian Hi-Tech and Spacetime have also proposed their own IoT constellation system development plans. The "Apocalypse Constellation" consists of 38 low-orbit satellites, of which 7 are currently in orbit and providing satellite IoT data services. It can provide satellite data services to global IoT users and realize a satellite IoT ecosystem that integrates "air, space, land and sea". my country's first "space-based IoT" is named "Xingyun Project", which will form a global IoT information system by building a constellation system of 80 low-orbit communication satellites.

At the application level, China Mobile successfully completed the commissioning and debugging of 5G SA base stations using the ChinaSat-16 high-orbit satellite, opened up the communication process between the ground and satellite systems, and successfully carried out business trials such as file transfer, video calls, and high-definition video on demand. China Unicom and CASIC completed the first "5G + low-orbit satellite" integrated network service demonstration in China, and signed an air-ground integrated strategic partnership agreement with Galaxy Aerospace, accelerating the construction of an air-ground integrated communication network.

At the standards level, in August 2019, the China Communications Standards Association (CCSA) established the Space Communications Technology Working Committee (TC12). As one of the three working groups, the "Collaborative Networking Communication Technology Working Group" focuses on collaborative networking in multiple modes including air, space and ground.

3. Main difficulties faced

Although some progress has been made in promoting the integrated sky-ground information network both at home and abroad, there are still many challenges in general:

1. Risks of frequency resource competition and management

First, there is the risk of competition for frequency resources. Currently, the competition and sharing of 5G and satellite spectrum resources are already very prominent. As many countries have proposed low-orbit communication satellite constellation plans, limited satellite frequency and orbital resources are facing almost unlimited growth demand, and the risk of competition for frequency resources is increasing.

The second is the problem of satellite frequency interference. The NGSO satellite constellation proposed in recent years contains a large number of satellites and covers the entire world, using the Ku and Ka bands that overlap with traditional geosynchronous orbit (GSO) satellites.

(II) The technology complexity of the integrated space-ground network is relatively high

First, there is a generational gap between the space-ground network. Although the satellite communications industry has also developed significantly in recent years, it is still relatively slow compared to the progress of ground communications. Low-orbit satellite communications based on 5G must make adaptive improvements and targeted optimization designs on some key 5G technologies.

Second, the space-ground integrated network is more complex. Compared with traditional communication networks, the space-air integrated network involves multiple communication systems, and some access nodes have strong mobility, so higher requirements are put forward in terms of network structure, communication facilities and equipment, air interface and network management technology.

3. Poor service consistency and demand certainty

First, the consistency of space-ground network services is poor. Differences in terminal capabilities, network capabilities, and service requirements lead to heterogeneity in network application capabilities of the space-ground integrated network, which poses a challenge to service consistency and makes different services self-contained and interoperable.

Second, the uncertainty of network demand is relatively large. The market for integrated sky-ground networks is still in the development stage, and there is a certain degree of uncertainty in market demand.

(IV) Cybersecurity risks

First, security issues are prominent in the process of building an integrated sky-ground network, which faces security risks in network architecture, key management, routing protocols, network security switching, and network data transmission.

Second, cross-border regulation of satellite Internet is a prominent issue. Satellite Internet systems have the natural characteristics of cross-border coverage and global communication, and can achieve direct communication without passing through domestic ground network systems, breaking through traditional ground Internet information supervision. How to identify satellite constellations that have not obtained my country's landing rights through satellite monitoring, and the actual business operations in my country face challenges.

(V) Risk of capital chain rupture

The space-ground integrated network is an asset-heavy operation, with a large initial capital demand, high costs for satellite production and launch, and a lack of self-sustaining capabilities in the early stages of development. Most private satellite Internet companies rely heavily on external financing. However, in today's satellite industry, which is facing the dual contradictions of intensified competition, soaring operating costs, and long investment cycles and slow returns, the capital chain of private aerospace companies is at risk of breaking.