Research On Key Technologies Of Satellite Cooperative Transmission In Space Information Network

After decades of development,satellite communication has been widely applied in the fields of resource exploration,navigation,weather forecast,communication.Due to the different function between these satellite systems as well as the lack of unified and effective standard between different data communication interface,the information between different systems cannot be effectively shared in space information network,which leads to the huge waste of valuable resources in space information network.In order to break through the existing single link transmission bottleneck and improve the users' quality of experience,it is need to adopt bandwidth allocation scheme with cooperative transmission.In addition,if we cannot solve the problem of how to make LEO satellites access the space network backbone nodes effectively,the research on cooperative transmission in space information network will lose its practicability.Traditional single-link transmission scenario could no longer satisfy the users' need because of the limited communication capability and isolated working style.In the thesis,a cooperative transmission scenario in multi-layered satellite network has been designed.Then,a QoE-aware based bandwidth allocation algorithm in distributed constellation network has been proposed,introducing an uplink link utility function,which quantifies not only the match-degree of traffic types and networks,but also the wireless transmission capacity and wireless resource cost.And the bandwidth allocation decision-making is formulated as a convex optimal problem and solved with Karush-Kuhn-Tucker conditions to maximize the overall utility function.In this thesis,the proposed algorithm increases the resource utilization and improves the users' satisfaction level for communication services,which can be interpreted as network diversity.This thesis designs the users' Quality of Experience evaluation models of different traffic types,which apply to solving the heterogeneous GEO satellite network access problem.On the basis of these evaluation models,this thesis proposes a network access selection algorithm based on evolutionary game theory.The reward function,which determines the users' network access selection decision,mainly considers the users'Quality of Experience and signaling overhead.When LEO satellites update the access strategy,LEO satellites tend to select the GEO satellite network,which could improve satellites' quality of experience.This network access selection algorithm could alleviate the pressure of the network and implement equal access reward between different LEO satellites.