摘要
In a Low-Earth Orbit (LEO) satellite network, each satellite covers an area for a limited time interval. Thus, once the serving satellite is about to lose coverage of the area, a handover needs to be performed to let another satellite take over serving the user equipment (UE) in the area. Although many LEO handover algorithms have been proposed in the literature to date, none of them can ensure the minimum handovers of UEs (or the minimum average call blocking rate of satellites) when the network resource is sufficient (or insufficient). In the paper, we fill this gap by proposing two graph-based algorithms for networks with sufficient and insufficient resources, respectively. Simulations show the proposed algorithms have significant improvements in the number of handovers of UEs and the call blocking rate of satellites over the state-of-the-art methods.