Joint Route Selection and Resource Allocation Algorithm for Data Relay Satellite Systems Based on Energy Efficiency Optimization

In this paper, we consider a data relay satellite (DRS) system which consists of a geosynchronous earth orbit (GEO) satellite, a number of source low earth orbit (SLEO) satellites, relay LEO (RLEO) satellites and destination ground stations (GSs). We assume that a number of date flows with a fixed traffic volume are required to be transmitted from their SLEO satellites to destination GSs. The joint route selection and resource allocation problem is addressed for the DRS system. By defining system energy efficiency as the sum of the energy efficiency of the SLEO satellites and the RLEO satellites, the joint route selection and resource allocation problem is formulated as an energy efficiency maximization problem. As the original optimization problem is NP hard, which cannot be solved conveniently, we transform it into three subproblems, i.e., power allocation subproblem, inter-satellite route selection subproblem and end-to-end route selection subproblem, and solve the three subproblems by means of Lagrange dual method, Dijkstra's algorithm and Kuhn-Munkres matching algorithm, respectively. Numerical results demonstrate the effectiveness of the proposed scheme.