Research And Simulation Of Cross-Layer Multi-path Routing For Space Information Networks

With the rapid development and wide application of aeronautical and space technology, space is becoming increasingly important strategically in political, military and economic fields. Thus the research and application of space information networks have attracted a great deal of attention in all countries. With the characteristic of highly dynamic topology, very limited on-board processing capabilities, large propagation delay of inter-satellite links and great delay jitter in space information networks, routing faces serious challenges.By considering that the nodes move in orbits and their motion is periodical and predictive, network operation time is divided into a series of time slices. With in a time slice, nodes which can form a stable topology are defined as backbone nodes, while nodes which are hard to attribute to backbone network are defined as non-backbone nodes. The proposed cross-layer multi-path routing protocol designed for space information network are achieved on the base of time slice division. Based on the traditional TCP/IP protocol stack, the cross-layer information exchange module is added, which breaks the restriction of the original layer structure and realizes information sharing among the layers. The function of cross-layer information exchange enable routing protocols adapts to the changes of the network automatically according to services QoS requirement and the conditions provided by the network. When routing initializes, multi-paths are selected in terms of rout total bandwidth and communication delay, which achieves load balancing and improves fault tolerance in routing. During steady running period, information from physical layer, MAC layer and networks layer are collected to reflect network status changes in accurately and timely manner. According to different application requirements of delay sensitive services, bandwidth sensitive services, high reliability sensitive services and so on, network dynamically make adaptive choose of routing strategies. For special services with high QoS requirement, bandwidth reservation mechanism is used to achieve route adaptive, self-configurable, load-balancing and efficient routing. Based on the simulation of space information networks by STK (Satellite Tool Kit), time slice is divided and network topology is established. According to the simulation results of routing algorithm using NS network simulation software, the proposed route protocol can adapt to the network conditions and traffic requirements, and is suitable to be applied to space information networks with great routing performance.