Research On Reliable Transfer Protocol In Space Communication

Innovative development of space and network technology has promoted dramatically change in future network structure.For instance,how the satellite network communicates and integrates with existing Internet has been a hot research subject.Moreover,deployment of air and space integration network in next-generation has promising prospects.Due to space communications environment with a large link delay,error rate,easy to break,forward and reverse link asymmetric features,the existing Internet TCP/IP protocol cannot well adapt to this environment.CCSDS(The Consultative Committee for Space Data Systems) has proposed and developed an adaptation space network SCPS protocol cluster on the basis of TCP/IP.It is particularly significant to design protocol gateway in order to integrate satellite network and Internet construction,make TCP/IP and SCPS protocol cluster work effectivelly in their role and deal with various problems in the network convergence.In this paper, we firstly introduce the domestic and global researches in cyber network protocol and network fusion between the aerial and the terrestrial. In chapter 2, the data structure, the establishment and termination for connectivity, the traffic and the congestion control in transport layer of TCP protocol are illustrated in details.In chapter 3, we attach the emphasis on comparison between SCPS-TP and TCP protocol in their difference for strategies of handling complicated space communications, such as the header compression in SCPS-TP protocol, the Vegas congestion control algorithm and the SNACK algorithm. Based on these studies, we propose a novel translation gateway to achieve the switch between the TCP and the SCPS-TP protocol. The principle in designing this proposed gateway is the TCP splitting technique, which employs the segmented processing method in communication link and use the cheating approach for data transmission. Specifically, the TCP protocol is selected for the transmission in the terrestrial communication link, and the SCPS-TP protocol is chosen for the aerial space communications with the switch processing of the proposed gateway. In this paper, we elaborate the principle of protocol gateway in connectivity management, buffer management and data transformation. This novel design of protocol gateways sufficiently considers the difference between the terrestrial link and the space link, Which makes TCP and SCPS-TP can be converted, improves data transmission success rate and reduces the requirement for the size of the storage on the space device hardware. To demonstrate the analysis, we build a simulation model, and use the MATLAB to validate the performance of our proposed protocol gateway, presenting the different results between TCP and SCPS-TP protocol. We compare the link throughput between TCP and SCPS-TP protocol on the basis of fixed time delay and bit error rate, respectively. The simulation results turns out that the performance of SCPS-TP is better than that of TCP when the time delay and bir error rate is high.