| With the exploration of space gradually from the near space to the deep space in the solar system and cosmic space.The exploration of deep space environment not only helps people understand their living environment better,but also promotes the continuous development of science and technology.A key technology for deep space exploration is needed to solve the deep space communication network.The deep space communication network is different from the traditional information transmission network,It has the characteristics of the frequent interruption of network link,long transmission distance and long time delay,which requires re-correct the traditional network communication protocol and even set up a new protocol architecture in order to ensure the reliable transmission of deep space communication information.The delay tolerant network research group(DTNRG),first proposed the concept of the delay tolerant network DTN,which is the standard architecture for deep space,based on this architecture.How to improve the protocol performance,such as congestion control,is the main content of this paper.Firstly,this paper introduces the communication theory and key technologies used in deep space link,which is used to solve the problems of the frequent interruption of network link,long transmission distance and long time delay.Then,this paper analyzes the bundle protocol for DTN protocol architecture and three typical convergence layer protocols.Among them,the communication flow of LTP transport protocol is analyzed emphatically,The characteristics of the three protocols are compared from the theoretical level,theoretical support for the following simulation scenario building and system simulation is provided.Secondly,a typical Mars exploration mission is chosen as the Research scene.According to the characteristics of the fire communication link,by using the STK software,a simulation model of the fire communication link is build.On this basis,the performance of the convergence layer protocol is simulated and verified,analyzed the influence of characteristics of asymmetric channel index ratio,BER,link interruption time to typical transmission protocol architecture based on model caused by fire.The result shows that the LTP protocol has a higher throughput than the other two protocols in the deep space environment,but there is plenty of room to speed things up because LTP does not have a congestion control mechanism.According to the LTP protocol application in the deep space communication network scene,The key factors that affect the performance of deep space communication network are defined.The adaptation characteristics and existing problems of different congestion control strategies are analyzed,and the performance is verified by simulation software.Finally,in view of the application of some congestion control strategies in DTN networks,a hybrid filtered data transfer memory adjustment algorithm is proposed to realize congestion control.The basic idea is to complete the data transmission through the storage pressure transfer to the adjacent node and re planning the optimal transmission path,and the ION performance of the algorithm is verified.The performance of the algorithm is verified,and the results show that the algorithm improves the data delivery rate and reduces the packet loss rate. |
