Research On Key Technologies Of Application IP Over CCSDS Link In Space Communication Network

With the development of manned spacecraft mission and deep space exploration program, especial the decision to launch space lab and space station, space missions become diverse and need cross support very much, thus make space-ground communication more difficult and challenges. To meet these needs, it requires support of the space TT&C communication network, the connection of spacecrafts and the space networks connect to the terrestrial networks, therefore make the current space to ground data transfer mode change to satellites data relay mode; it also demands that the space-ground communication networks can provide more data transfer methods, makes the interactive and multi-service capabilities better, bandwidth wider, access and extend easier, more efficient, and changes the current simple data exchange to the end-to-end network exchange. It is obviously that the current point-to-point space-ground communication network cannot meet these needs, and it is much desired to establish the national space TT&C and data exchange communication networks, and thus changes the space technology status of our country.Based on these requires, the paper analyses the technologies that adopted by the international space organizations in space data system at first, proposes the method for establish the space communication networks based on IP over CCSDS AOS that fits the future development needs of our country, and then designs the infrastructure of the networks and analyses the key technologies, sets up the space-ground communication networks protocols stacks, supplies a gap in this research field of our country.The paper proposes the methods and also the interfaces to transfer IP datagram using CCSDS AOS. For IPv4 over CCSDS and IPv6 over CCSDS, it sets up the protocols stacks and analyses the data transferring services process procedures, including CCSDS AOS VCP service, ENCAP service; and also the data transferring services application modes and the relative protocols process procedures.The mobility of the satellites networks makes the regular IP technologies not appropriate for IP over CCSDS networks and has to take the mobile IP technologies instead. Considering the problems of IP technologies in satellites networks, such as varying IP datagram size, complicated space links, difficult to manage routing tables and the very short routing switch time, the paper discusses the tunneling and routing technologies of mobile IP. In the end of this chapter, the paper designs the Mobile IP over CCSDS AOS communication mode, which is the first design in our country.IP is faced to datagram but not connection, it does not guarantee the reliable data transfer, but TCP is designed to guarantee the end-to-end reliable data transfer, so the space communication links will have effects on transport layer of IP over CCSDS networks. The paper analyses the fundaments and the relative control mechanisms of the regular TCPs and also the effects of space communication environment on them, makes a conclusion that regular TCPs is not appropriate for space communication.The paper takes SNACK, one of the advises proposed by SCPS-TP, as the improvement strategy to make some changes on regular TCP NewReno in NS2, and thus makes the TCP SNACK space communication network simulation model. By comparing the throughput, drop rate, link utilization, etc, between the regular TCPs and TCP SNACK. It concludes that the TCP SNACKhas the best performance among the regular TCPs in space communication environment and more fit for the IP over CCSDS space communication network system.It is reasonable and efficient to take the IP over CCSDS AOS as the future space communication networks technology. The research results of the paper will be the important supports for the unify and integration of the space networks and the terrestrial networks; for transferring payloads data with audio and video data simultaneously, for improvement of the efficiency and extension of communication system and reduce the costs at the same time; and also prepare the necessary technologies for the application of telescience research and the international cross supports.