Hybrid Retransmissions of Bundle Protocol for Reliable Deep-Space Vehicle Communications in Presence of Link Disruption

Targeted as the main protocol of delay/disruption-tolerant networking (DTN) for space, bundle protocol (BP) is intended to establish an overlay network for reliable file delivery in a heterogeneous networking environment. Reliable data transmission mechanisms of BP are presently under development. In this paper, a new transmission approach is proposed for BP for highly reliable data delivery in deep-space communications in presence of an unpredictable or random link disruption. The main idea of the proposed approach is to use a hybrid of proactive transmission and reactive transmission mechanisms during file transfer. Analytical models are built in various transmission cases to study the effect of link disruption on reliable transmission of BP, with focus on the number of failed transmission attempts, file delivery time and goodput performance normalized with respect to the total amount of data sent. The models are validated by the file transfer experiment over a PC-based testbed. A performance comparison between the proposed approach and the existing transmission approach with respect to transmission reliability is also presented.