基于深空通信的LTP协议性能与内存研究-通信与信息系统专业论文.docx

I II Abstract A Study on Performance and Memory Occupancy of LTP for Space Communication A Study on Performance and Memory Occupancy of LTP for Space Communications Abstract Delay/disruption tolerant networking (DTN) was developed to enable automated network communications despite the long link delay and frequent link disruptions that generally characterize space communications. The performance of DTN convergence layer adapter (CLA) protocols over asymmetric space communication channels has not yet been comprehensively characterized. In this paper, we present an experimental performance evaluation of DTN CLA protocols for reliable data transport over a space communication infrastructure involving asymmetric channel rates, with particular attention to the recently developed Licklider transmission protocol (LTP) CLA (i.e., LTPCL). The performance of LTPCL is evaluated in comparison with other two reliable CLAs, TCPCLA and a hybrid of TCP CLA and LTPCL, for long-delay cislunar communications in the presence of highly asymmetric channel rates. LTPCL is also evaluated and analyzed in a deep-space communication scenario characterized by a very long linkdelay and lengthy link disruptions. The Licklider Transmission Protocol (LTP) of DTN is aimed at enacting retransmission service comparable to that provided by the Transmission Control Protocol (TCP). While LTP’s window structure limits the number of data items in the window, it does not limit data item size; the total volume of memory occupied by the data items in the window may vary over time. Since this variation in memory occupancy constrains the volume of memory that is available for other DTN functions, it is important to characterize the conditions under which data may be added to or removed from the window. In this paper, we present a study of memory allocation dynamics for LTP-based transmission in a typical relay-based deep-space communication system characterized by an extremely long signal propagation delay, los