Research On The Topology And Routing Protocol Of Multi-layered Satellite Network

Communication satellite network plays an important role in the space strategy of our country and attracts more and more attention. To design communication satellite networks which meet the need for our country will have important political, economic and military significance.Network topology and routing protocol are hot subjects in research topics of communication satellite network. Due to the strict limitations and enormous time cost to build inter-satellite links, a stable network topology has great influence on the performance of a communication satellite network. We research on the topology and routing protocol of the multi-layered satellite network, which comprises GEO(Geostationary Earth Orbit), MEO(Middle Earth Orbit) and LEO(Low Earth Orbit) satellites.This thesis takes advantage of STK(Satellite Tool Kit) to design the walker delta constellation for MEO/LEO satellite layers, which can provide permanent links. In our design, nodes in the same layer make up the stable topology with permanent links, with GEO satellites constituting ring with chords, while MEO/LEO satellites constituting 2D-torus respectively. To decrease the degrees of coupling, and to balance the inter-layer links between different layers, this thesis divides the earth surfaces and forms clusters'nodes in different layers according to its projective location on the earth. Only the different layer nodes in the same partition will establish the inter-layer links, thus form a three-layered network with balanced overload, redundancy and satisfactory links.As for routing protocol, we design the routing protocol of the multi-layered satellite network aimed for minimum communication latency. And then according to the packets'type, we design different kinds of node address matching and data forwarding mode, to accelerate the transmission of the data packets and other routing messages.Simulation was carried out in the multi-layered satellite network environment established in OPNET Modeler, with the routing protocol implemented, and performance of the topology and routing protocol tested. Simulation results show that the topology of the network is stable and robust, and the routing protocol has good performance in the load balancing and node failure adapting.