Mobility Management Scheme in Integrated Satellite-Terrestrial Communication System

Integrated satellite-terrestrial network (ISTN) has attracted widespread attention due to its ability to fully utilize the advantages of high transmission rate, low propagation latency, mature technology of terrestrial network (TN), as well as the advantages of large coverage and good disaster tolerance of non-terrestrial network (NTN). However, in ISTN, the high-speed low earth orbit (LEO) satellites make the system face frequent handover problems. Therefore, mobility management solutions in ISTN are investigated in this paper. Firstly, an ISTN architecture that can support inter-LEO satellite handover and the handover between satellites and the ground is proposed. On the basis of this architecture, co-orbital and cross-orbital satellite handover schemes are proposed respectively, and the cross-orbital handover can be realized without the need of cross-orbital inter satellite links, reducing the requirements for on-board processing capabilities. In addition, satellite-to-ground and ground-to-satellite handover schemes are proposed, which can adaptively select TN or NTN to provide services for terminals based on different service requirements and channel environments, thus maintaining the continuity of user services, reducing energy consumption, and ensuring real-time and effective services.