Joint access node selection and fast routing optimization for LEO satellite networks

The low Earth orbit (LEO) satellite networks play an important role in the future communication networks. However, under the end-to-end (E2E) transmission background, inter-satellite routing has been widely studied, but the influence of ground-satellite links (GSL) on routing has received less attention. In this paper, a fast E2E satellite routing algorithm based on access node selection is proposed. Firstly, the delay of four path modes generated by users accessing the network from different satellites is analyzed, and the influence of delay on E2E routing performance is presented. Then, jointly considering routing delay and node load, an access node selection strategy is proposed by using the shortest E2E delay to determine the access source and destination node within satellites. Finally, an optimization domain is divided from the network topology by using the shortest delay path based on hops constraints. And a routing optimization algorithm based on Q-learning has been proposed in the optimization domain, realizing high computational speed and stable results. The simulation results show that the access node selection strategy can decrease E2E delay by up to 10 ms and enhance the performance of node load balancing. And the routing optimization algorithm can reduce the average computation time.