By analyzed the scenario characteristics of 6G integrated satellite and terrestrial network, the current state of research on edge computing capabilities on satellite, and the demand of cloud-edge collaboration, a network architecture that combines computing power network technology to achieve cloud-edge collaboration for integrated satellite and terrestrial networks was proposed, and global resource awareness and collaborative policy scheduling for integrated satellite and terrestrial networks by introducing a network function cloud-edge collaboration function was achieved .Based on this architecture, a unified resource management mechanism of the integrated satellite and terrestrial network was proposed, included a global resource awareness technology that could managed the computing and network resources of the integrated satellite and terrestrial network, and a policy generation technology that could collaborate with the computational capabilities of the cloud-edge and the integrated satellite and terrestrial network.Finally, the rationality of the cloud-edge collaborative architecture proposed in this article, as well as the correctness of resource awareness technology and policy scheduling technology, were verified through a self-developed mobile communication network platform.

With the development of ubiquitous and broadband communication requirements and the satellite-ground integration communication technology, the satellite and ground cellular communication industry ecosystem is gradually moving towards integration.In order to meet the application scenarios and technical requirements of satellite-terrestrial cooperation, the main technical challenges of the access network architecture were analyzed.Based on the overall principles of connection dynamics, unified resource management and controlled by ground network, the architecture of access network for satellite-terrestrial cooperation was elaborated from space segment, ground segment and cooperative segment.Key technologies of coverage cooperation, service cooperation, energy saving cooperation and capability cooperation were proposed based on the elaborated network architecture.By design cooperative network elements, such as intelligent dynamic cooperative unit, dynamic Xn interface, distributed TT＆amp;C units, the useful information between satellite and ground networks interacted deeply, a dynamic and efficient satellite-terrestrial cooperation mechanism could be realized.It could promote further complementarity between satellite and ground networks and improved overall system performance in resource utilization rate, energy consumption, and network construction cost.

With the public land mobile communication network transitioning from the 5G era where information flows freely to the 6G era where everything is interconnected, satellite networks have become a hot development topic all around the world.At the same time, with the improvement of satellite on-board computing capabilities and the integration of computing and satellite networks, cloud network integration has become a new development trend.On the basis of a brief introduction to the current development status of satellite networks and satellite computing, the development roadmap of satellite network development architecture was summarized.Then, a satellite network architecture based on cloud-network integration (i.e.satellite cloud network) was proposed, and the advantages of satellite cloud network architecture from five aspects: computing driven communication enhancement, computing driven network enhancement were analyzed, computing driven service enhancement, computing driven control enhancement, and computing driven management enhancement.

For satellite internet of things (IoT) scenarios with high propagation delay and the need to serve a larger number of users, firstly the shortcomings of IoT NTN in terms of technical solutions were analyzed, and then a new type of multi access solution called uncoordinated random access and NOMA transmission (URAT) was proposed.“Uncoordinated” refers to the process where a terminal does not require specialized network coordination signaling; “NOMA transmission” refers to the sharing of base station time-frequency resources by all terminals; URAT also achieves the integration of multiple access and NOMA transmission.Theoretical analysis and numerical simulation results indicated that the proposed scheme could reduce multi access latency, improve system efficiency, and increase the number of devices that could be served.It will be a potential solution for the 6G satellite IoT scenarios.

The integration of communication and navigation is an important direction in modern satellite communication and navigation fields.The advancement of low earth orbit (LEO) mega-constellations provides the abundant load, link and terminal resources, as well as the powerful communication coverage and information transmission capabilities.Moreover, together with the fast-changing geometric configuration and strong power, the LEO satellites can complement, backup, and enhance the existing navigation systems to provide communication and navigation services with broader coverage, higher precision and reliability.In the LEO satellite-enabled communication and navigation-integrated system, the design of the transmitted signals and the processing of the received signals are crucial for achieving efficient communication and high-precision navigation.To this end, the evolution process of the communication and navigation fusion was first outlined.Then, it focused on the design of transmitting signals and the processing of receiving signals, the relevant schemes included the layout of the frame structure and the receiver were emphasized, respectively.Finally, the challenges and potential solutions that lie ahead in the future were explored.

With the rapid advancement of aerospace technology and satellite internet, high-speed and high-bandwidth satellite communication systems have gradually become an essential component of the next-generation mobile communication infrastructure.The trend in the development of satellite internet has propelled the commercialization process of satellite networks, with low earth orbit satellites playing a significant role in constructing satellite internet.The efficient and reliable network management of large-scale low earth orbit satellite networks, along with the integration of space and ground routing, has gradually emerged as a cutting-edge issue in the development of integrated aerospace networks.In recent years, as satellite networks have expanded in scale, numerous network management methods have been proposed.Firstly, begined by examining the development status of large-scale satellite constellations both domestically and internationally, surveying the existing network architecture and protocol systems of various satellite networks.Subsequently, based on the current development status of large-scale satellite networks, the challenges and key technologies involved in satellite management were analyzed.Finally, built upon the network integration of space and ground, existing solutions were extensively researched and analyzed.

The high-speed motion of low-earth orbit communication satellites results in a highly dynamic network topology, and the spatio-temporal distribution of resources in the satellite-terrestrial integrated network is non-uniform.When multiple users and services switch between satellites, a large number of handover requests are triggered, leading to intensified network resource competition.As a result, the limited satellite resources cannot meet all the handover requests, leading to a significant decrease in handover success rate.In view of the above problem, the multi-objective optimization based satellite handover method was proposed.It introduced the satellite coverage spatio-temporal graph and transforms the dynamic continuous topology into static discrete snapshots, accurately depicted the connections between satellite nodes and users at different times and locations.The multi-objective optimization model was established for satellite handover decisions, and anadaptive accelerated multi-objective evolutionary algorithm(AAMOEA) was proposed to optimized user data rate and network load simultaneously, ensured handover success rate and enhanced network service capability.It built a STIN communication simulation environment and tested the multi user handover performance in a multi satellite overlapping coverage scenario.The results demonstrated that the multi-objective optimization-based satellite handover method achieved an average handover success rate improvement of over 20% compared to benchmark algorithms.

The traditional analytical method greatly underestimates the throughput capability of the system in low beam density scenario, and cannot reveal the capacity saturation phenomenon in high beam density scenario.To overcome the preceding problems, a new system simulation method was proposed to accurately evaluated the capacity density indicator of satellite constellation network and integrated satellite and terrestrial network, Based on this method, first, the capacity density of different longitude and latitude regions of the earth was evaluated.It could be observed that the capacity density of the same region varies greatly with the movement of the satellite, and the maximum capacity density was twice the minimum.Then, areas with higher visibility usually had higher capacity density.In high-frequency scenarios, the impact of atmospheric attenuation on capacity density could not be ignored.Finally, for the integrated satellite and terrestrial network, the evaluation results showed that the capacity density of cellular coverage and satellite coverage could differ by four orders of magnitude.In order to improved the capacity density of satellite constellation network, two technical paths were attempted: increasing the maximum number of illuminated beams and increasing the satellite scale.The results showed that the performance was better when the constellation scale was increased when the total beams of the constellation were the same.However, the two ways to increase the total number of beams in a constellation had an upper bound on capacity, and the marginal effect decreased significantly.Finally, a scheme to increase the gain of satellite antenna was proposed.The simulation results showed that the proposed scheme could significantly increase the capacity density of constellation.

The integrated satellite-terrestrial communication system is considered one of the development trends of future communication systems for its ability to provide seamless coverage and service.However, the differences between satellite and terrestrial communication networks, e.g., large propagation delays, large Doppler shifts, and large cell radius, pose challenges to fulfilling integrated satellite-terrestrial communication systems.The network architectures and key enabling technologies were discussed and analyzed and a prototype system for the terrestrial verification of integrated satellite-terrestrial communication systems was proposed.

Low-earth orbit satellites have the advantages of wide bandwidth, low latency, and large coverage, making them very suitable as a supplement to ground cellular networks.Low-earth orbit satellites can meet the requirements of smart high-speed railway full line coverage and seamless connection, which helps to build an integrated communication network between ground and space.Considered the shortcomings of the current railway mobile communication network, the application and key technologies of low earth orbit satellites in smart high-speed railway were studied.Firstly, the communication requirements of smart high-speed railway were analyzed, and then the development status of railway satellite communication at home and abroad were introduced.Finally, the key technologies and challenges of low earth orbit satellite application in the field of smart high-speed rail were discussed from the aspects of propagation characteristics, physical layer parameters, beam handover, and resource management.

Satellite internet is an important means to meet the ubiquitous network access in the future.It has a wide range of application scenarios in disaster prevention, marine operation and scientific research broadband on account of its wide coverage, large communication capacity and global seamless connection.Started from the vision of the deterministic transmission of satellite internet, combined with the existing deterministic network technology, the satellite deterministic network architecture was put forward, and the existing challenges and future development in deterministic access, multi-service differentiation guarantee, dynamic resource allocation and path backup of satellite deterministic network were pointed out.

Firstly, the difficulty of upgrading and expanding the traditional security service equipment were analyzed, and a design of an intelligent security access platform was proposed.Then, the research and development ideas and technical routes of the intelligent security access platform were explained, and hardware and software were designed.Finally, the platform achievement test and application deployment construction were carried out to verify the value of the platform.