空间通信自适应文件传输协议设计  

Design of adaptive retransmitted file delivery protocol in space communication

作　　者：王洋[1] 杨宏[1] 陈晓光[1] 陈淞[1] 

机构地区：[1]中国空间技术研究院载人航天总体部,北京100094

出　　处：《中国空间科学技术》2017年第3期53-61,共9页Chinese Space Science and Technology

摘　　要：现有的基于调整重传次数来降低文件传递时延的算法,或固定地重传丢失的协议数据单元(包)两次,或仅根据丢包率来调节重传次数,没有考虑到包个数、丢包率、链路单向传播时延与单个包发送时延之比等影响因素。文章基于延迟型否定应答文件传输协议,提出了一种用于空间通信的自适应调节重传次数的文件传输协议。对该协议的文件传递时延和额外传输开销性能进行了理论建模,分析了重传阶段包重传次数对重传回合数和重传包总个数两方面的影响,提出了自适应调节模块的设计方案。理论分析和仿真结果表明,在地火通信、文件包个数为1k、丢包率为0.79条件下,相比于双重传文件传输协议和延迟型否定应答文件传输协议,分别缩短了55.69%和74.28%的文件传递时延;在地月通信、文件包个数为100k、丢包率为0.79条件下,相比于仅根据误码率调节重传次数的重复发送文件传输协议,缩短了28.05%的文件传递时延。CCSDS file delivery protocol(CFDP) was improved by double retransmission mechanism or setting the retransmitted times in view of bit error rate(BER).However,without considering the impact of the number of protocol data units(PDUs),packet error rate(PER)and the ratio of link propagation delay to PDU transmission delay,these schemes are not the most appropriate in specific space missions under different channel conditions.Based on CFDP,a new file delivery protocol adjusting the retransmitted times of lost PDUs adaptively(AR-FDP)was proposed in space communication.The theoretical models of filedelivery time and extra transmission effort of AR-FDP were established.Also,the effects of retransmitted times on the number of retransmission rounds and the number of retransmitted packets were analyzed and the scheme of the adaptive control module was presented.The theoretical analysis and simulation results indicate that the AR-FDP shortens the file delivery time by 55.69% and 74.28% compared to the double retransmission scheme and CFDP respectively in Mars-to-Earth communication with PDU number of 1k and PER of 0.79.In Moon-to-Earth communication,the AR-FDP shortens the file delivery time by 28.05%compared to the scheme adjusting the retransmitted times in view of BER with PDU number of 100 kand PER of 0.79.

关 键 词：文件传输协议 自适应 空间通信 文件传递时延 额外传输开销 理论建模 

分 类 号：TP919[自动化与计算机技术]