## 1 Introduction
The integration of satellite communication and ground networks is projected to become a cornerstone of the sixth-generation (6G) wireless communication system, enabling the achievement of ubiquitous Internet of Things (IoT) [10]. In future communication systems, non-ground networks and satellite communication technologies are gaining increasing attention and emerging as a prevailing trend in power communication development. Based on different orbital altitudes, satellites are classified into Geosynchronous Earth Orbit (GEO), Medium Earth Orbit (MEO), and Low Earth Orbit (LEO) satellites. Among them, LEO satellites have drawn significant attention from the academic community because of their global coverage, low transmission latency, low power links, and robust resistance to destruction. Compared to medium- and high-orbit satellites, LEO satellites operate at lower orbital altitudes, resulting in smaller path losses and shorter propagation delays. This enables them to provide better data transmission rates and higher throughput [11], reduce transmission power, better mitigate signaling attenuation, and contribute to reducing the dimensions of terminal equipment [12], lowering the energy consumption of communication equipment, and enhancing the overall effectiveness of the satellite network. LEO satellites have extensive development prospects. As shown in Figure 1, constructing a wireless transmission network centered on LEO satellite communications, featuring strong anti-destructive properties and low latency, can provide flexible, efficient, and reliable communication solutions for scenarios such as grid data collection and back transmission, emergency response, and so on. Unlike terrestrial cellular networks, LEO satellites move at high speeds around the Earth in set orbits, each offering a limited service duration to fixed ground terminals [13]. The challenges of exploring inter-satellite optimized handover algorithms in LEO satellite networks primarily arise from the high-speed movement of satellites and the rapid changes in their relative positions, resulting in continuous fluctuations in the signaling environment and network state. Due to the high-speed movement of satellites, users must selectively hand over among candidate satellites to maintain communication continuity, necessitating handover algorithms to minimize communication interruptions and delays. Furthermore, during real-world communication scenarios, the duration of user communication typically exceeds the visibility period of a single satellite, and due to the time-varying characteristics of satellites, it is necessary to analyze the dynamic topology of the satellite network, which varies at different moments [14], leading to differences in the handover diagrams formed by the set of candidate satellites. As the satellite's movement causes the user to move out of the coverage area of the current servicing satellite, ground users must continuously hand over to other visible satellites during the communication process to ensure communication continuity. Because of the high-speed mobility and short coverage period of LEO satellites, handover between grid users and satellites occurs frequently, which may increase communication delays and reduce connection stability. At present, one crucial and urgent research issue is the development of a feasible inter-satellite handover strategy in LEO satellite communication systems. This strategy is vital for minimizing the handover frequency between satellites and power terminals, ensuring stable communication links, enabling seamless services, and maintaining Quality of Service (QoS) for users. In terrestrial cellular networks, users typically base their handover decisions on received signal strength from terrestrial base stations. However, for users accessing satellite networks, only considering the received signal strength is insufficient. In satellite networks, factors such as the remaining service time of the access satellite and the system's load balance significantly affect the user's QoS.