Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in ter...Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in terrestrial communications.Accordingly,the Consultative Committee for Space Data Systems(CCSDS) developed CCSDS File Delivery Protocol(CFDP),which sets standards of efficient file delivery service capable of transferring files to and from mass memory located in the space segment.In CFDP,four optional acknowledge modes are supported to make the communication more reliable.In this paper,we gave a general introduction of typical communication process in CFDP and analysis of its four Negative Acknowledgement(NAK) modes on the respect of file delivery delay and times of retransmission.We found out that despite the shortest file delivery delay,immediate NAK mode suffers from the problem that frequent retransmission may probably lead to network congestion.Thus,we proposed a new mode,the error counter-based NAK mode.By simulation of the case focused on the link between a deep space probe on Mars and a ter-restrial station on Earth,we concluded that error counter-based NAK mode has successfully reduced the retransmission times at negligible cost of certain amount of file delivery delay.展开更多
In consultative committee for space data systems（CCSDS） file delivery protocol（CFDP） recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative ac...In consultative committee for space data systems（CCSDS） file delivery protocol（CFDP） recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative acknowledge and asynchronous negative acknowledge models.CFDP is designed to provide data and storage management,story and forward,custody transfer and reliable end-to-end delivery over deep space characterized by huge latency,intermittent link,asymmetric bandwidth and big bit error rate（BER）.Four reliable transmission models are analyzed and an expected file-delivery time is calculated with different trans-mission rates,numbers and sizes of packet data units,BERs and frequencies of external events,etc.By comparison of four CFDP models,the requirement of BER for typical missions in deep space is obtained and rules of choosing CFDP models under different uplink state informations are given,which provides references for protocol models selection,utilization and modification.展开更多
当前我国卫星数据的存储和传输,仍采用位流的、不可靠传输方式。为了在特殊的空间环境下实现高速可靠的数据传输,研究了空间数据咨询委员会(CCSDS)提出的文件传输协议(CFDP)的传输机理,并以此为基础,对CFDP协议在实际工程中应用做了一...当前我国卫星数据的存储和传输,仍采用位流的、不可靠传输方式。为了在特殊的空间环境下实现高速可靠的数据传输,研究了空间数据咨询委员会(CCSDS)提出的文件传输协议(CFDP)的传输机理,并以此为基础,对CFDP协议在实际工程中应用做了一些预先研究。提出了适用于星载大容量存储器(Solid State Recorder,SSR)的类文件化管理系统,并采用FPGA与CFDP软件相结合的方式实现高速数据存取。同时,结合特殊的空间数据传输链路,采用特殊的数据链路层同步码实现数据同步传输。最终实现星载大容量存储器上的文件可靠传输。展开更多
文摘Deep space communication has its own features such as long propagation delays,heavy noise,asymmetric link rates,and intermittent connectivity in space,therefore TCP/IP protocol cannot perform as well as it does in terrestrial communications.Accordingly,the Consultative Committee for Space Data Systems(CCSDS) developed CCSDS File Delivery Protocol(CFDP),which sets standards of efficient file delivery service capable of transferring files to and from mass memory located in the space segment.In CFDP,four optional acknowledge modes are supported to make the communication more reliable.In this paper,we gave a general introduction of typical communication process in CFDP and analysis of its four Negative Acknowledgement(NAK) modes on the respect of file delivery delay and times of retransmission.We found out that despite the shortest file delivery delay,immediate NAK mode suffers from the problem that frequent retransmission may probably lead to network congestion.Thus,we proposed a new mode,the error counter-based NAK mode.By simulation of the case focused on the link between a deep space probe on Mars and a ter-restrial station on Earth,we concluded that error counter-based NAK mode has successfully reduced the retransmission times at negligible cost of certain amount of file delivery delay.
基金supported by the National Natural Science Fandation of China (6067208960772075)
文摘In consultative committee for space data systems（CCSDS） file delivery protocol（CFDP） recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative acknowledge and asynchronous negative acknowledge models.CFDP is designed to provide data and storage management,story and forward,custody transfer and reliable end-to-end delivery over deep space characterized by huge latency,intermittent link,asymmetric bandwidth and big bit error rate（BER）.Four reliable transmission models are analyzed and an expected file-delivery time is calculated with different trans-mission rates,numbers and sizes of packet data units,BERs and frequencies of external events,etc.By comparison of four CFDP models,the requirement of BER for typical missions in deep space is obtained and rules of choosing CFDP models under different uplink state informations are given,which provides references for protocol models selection,utilization and modification.
文摘当前我国卫星数据的存储和传输,仍采用位流的、不可靠传输方式。为了在特殊的空间环境下实现高速可靠的数据传输,研究了空间数据咨询委员会(CCSDS)提出的文件传输协议(CFDP)的传输机理,并以此为基础,对CFDP协议在实际工程中应用做了一些预先研究。提出了适用于星载大容量存储器(Solid State Recorder,SSR)的类文件化管理系统,并采用FPGA与CFDP软件相结合的方式实现高速数据存取。同时,结合特殊的空间数据传输链路,采用特殊的数据链路层同步码实现数据同步传输。最终实现星载大容量存储器上的文件可靠传输。
