Topology Analysis of Inter-Layer Links for LEO/MEO Double-Layered Satellite Networks

Due to the relative orbiting of Low Earth Orbit (LEO) satellite and Medium Earth Orbit (MEO) satellite, the inter-layer links (IIL) of LEO/MEO Double-Layered Satellite Networks (DLSN) have to switch dynamically, resulting in dynamic changes of satellite network topology, which has an impact on the data transmission performance of DLSN. In this paper, the IIL topology of LEO/MEO DLSN is analyzed and simulated. Firstly, the visibility calculation method and establishment strategy of IIL between LEO and MEO satellite as well as the calculation and optimization of system snapshots is analyzed. Then, simulation analysis regarding the number and duration of system snapshots, IIL switching time for LEO, the number of switching IIL in each system snapshot, the number of IILs that each MEO needs to establish are presented. Finally, the future research trends of DLSN IIL topology are discussed, such as how to reduce the maximum IIL number for MEO and so on.