Research On The Integration Technology Of Space-ground Integrated Network

With the development of communication technology,the development of space network technology represented by satellite communication is progressing day by day.Due to the wide coverage of satellite network services and the advantages of small ground effect and flexible deployment,the advantages of ground networks can be compensated.Therefore,the integration of the space-ground integrated network has gradually become the trend of future technology development.However,the differences in application scenarios and protocol architectures between space networks and ground networks pose challenges to the effective integration of the technologies and architectures of the space-ground integrated network.The space network is influenced by the weather,the carrier is moving at a high speed,the celestial body is obstructed and the distance between the nodes is far away.As a result,the space network has long propagation delays,links are easily interrupted,and the BER is high.Compared with the space network,the ground network is relatively stable in transmission,with short propagation delay,continuous links,and low BER.In addition to differences in application scenarios,there are differences in network protocol architectures.The open space network uses different network protocols.Due to the initial design goals and other reasons,the interoperability between the protocols is low,and the data formats used by each are different.Since the differences in application scenarios and protocol architectures of ground networks and space networks,problems such as limited resource sharing and low resource utilization are caused.In order to achieve flexible and full sharing of network resources and efficient use of services,and to provide quality services and good quality guarantees for businesses,it is necessary to study and analyze the integrated network protocol system and key technologies in order to eliminate individuals based on the characteristics of heterogeneous networks in the world.Network barriers,laying the groundwork and providing guarantees for efficient use of resources and better services.This thesis takes the TCP / IP and CCSDS protocols as the representative,combines the characteristics of the ground communication system and the space satellite communication system,designs the protocol architecture of the space-ground integrated network,and carries on the thorough research to its key technology and key mechanism.The specific research content is as follows:(1)This thesis first introduces the structure and data format of the TCP / IP and CCSDS protocols,and analyzes the key mechanisms.Finally,it studies the SACK technology and the snack technology in depth.The working principle of this kind of technology is explained.(2)This thesis analyzes and integrates the key technologies of the space-ground integrated network in response to the differences in the world network.The key technologies of these integrations include data retransmission strategies,maximum transmission window settings,slow-start initial window settings,calculation of timeout timer values,interrupt responses,and header compression.Combining these key technologies of convergence,this thesis finally designs the protocol architecture of the space-ground integrated network,and gives the preliminary agreement system model.(3)There are many kinds of packet loss reasons for the space-ground integrated network,and two kinds of congestion control mechanisms are provided.One is a congestion control mechanism based on processing after packet loss has occurred,and the other is a congestion control mechanism based on prediction.The first integrated network congestion control mechanism is to improve the format of the SNACK technology so that it has Display congestion notification capabilities and take different approaches based on different data loss reasons.The second integrated network congestion control mechanism combines hop counts and an improved Vegas algorithm to accurately differentiate the causes of packet loss.And take different measures for different reasons.Finally,this thesis simulates two kinds of congestion control through NS2 software,which proves that the two congestion control mechanisms have a certain increase in the throughput of the network.