IoT Gateway Association and Data Scheduling for Delay Optimization in LEO Satellite Systems

As a critical supplementary to terrestrial communication systems, low-earth-orbit (LEO) satellite communication systems have been gaining growing attention in recent years. In this paper, we consider an LEO system where a number of Internet of things (IoT) gateways need to send their collected data to LEO satellites. The highly dynamic topology of satellite systems and the limited connection status between satellites and gateways pose challenges to the problem of gateway association and data scheduling. To address this problem, we define system transmission delay as the number of time slots needed for all gateways to upload their collected data, and formulate the joint gateway association and data scheduling problem as a system transmission delay minimization problem. To solve the problem, we first consider a relatively simple case, i.e., a single gateway case, and propose a greedy method-based single gateway association and data scheduling algorithm. We then extend the solution to the case of multiple gateways and propose a transmission priority-based joint gateway association and data scheduling algorithm. Simulation results show that the proposed algorithm is superior to the algorithm proposed in previous work.