Task-Aware Distributed Inter-Layer Topology Optimization Method in Resource-Limited LEO-LEO Satellite Networks

Abstract

<p>Due to the increasing demand for real-time observation data, remote-sensing satellites can be considered as users to access mega communication constellations, which can constitute a Low Earth Orbit (LEO) Double-Layered Satellite Network (DLSN) composed of Remote-sensing Layer Satellites (RLSs) and Communication Layer Satellites (CLSs). In this LEO DLSN, a Distributed Inter-Layer Topology Optimization (DITO) method is proposed based on time-space relationships between two layers, which can maximize task-aware observation benefits with limited onboard resources. For practical purposes, we take link switching interval constraints into account for the recapture and track of laser communicators. Besides, we put forward a new time-slot division method based on the link switching interval for the linear modeling of the time-sequential coupling problem. With the simulation results in four constellation systems, the proposed distributed interactive method can obtain an optimal solution close to the centralized global solution with much less time. Simulation analysis indicates that the work of this paper can support onboard optimization for future space networks.</p>

Link Topology and Multi-Objective Mission Flow Optimization for User Satellites with Inter-Layer Links and Satellite-Ground Links

“…is the connectable relationship matrix and can be obtained according to the authors' previous work in [22],…”

“…Inequalities ( 21)-( 22) are the norm constraints of vectors and can guarantee enough link switching time for ILLs since the recapture is essential for inter-satellite laser communications. The detail explanation of ( 21)-( 22) can be found in the authors' previous work [22]. Note that the time-slot duration ∆τ c needs to be longer than the necessary link switching time.…”

“…Therefore, we plan SGLs and ILLs from the perspective of each user satellite and consider the planned links as the final topology. If communications satellites and ground stations have limited linking devices, we can add a distributed request and reply process between step 5 and step 6 refer to the authors' previous work in [22]. It means that each user satellite requests corresponding objects for SGLs and ILLs, and each communications satellite and each ground station can reject some requests according to its linking limits.…”