A Novel Joint Scheduling Scheme of Earth Observation and Transmission in Satellite Networks

Earth observation scheduling and the observed data transmission have complicated coupling relationship. To make full use of the observation and transmission resources in satellite networks, we propose a graph based joint scheduling strategy to combine the information of the sensing and transmission phases, and to maximize the resource utilization, where the conflicts during both the observation and the transmission phases are carefully examined. To be more explicit, in the sensing phase, we depict conflict relations among the satellites and the tasks with conflict graphs. And with virtual links inserted, the conflicts are transferred into node and link constraints. With respect to the transmission phase, we characterize the transceiver resources with virtual links to support on-demand resource allocation when the transceiver resource conflicts happen. Finally, we obtain the time-varying opportunity graph(TVOG) through characterizing the time-varying network topology and incorporating the conflict resolution graphs, and solve the problem with maximum flow algorithm in TVOG. The simulation results demonstrate the performance of our joint scheduling scheme in terms of effectiveness and efficiency.