Mobility Management for Novel Cooperative Two-Layer Satellite Network

Only relying on a single satellite cannot ensure the wide coverage, low delay, and high communication quality at the same time. Thus, a novel cooperative two-layer satellite network architecture is proposed in this paper. In the proposed architecture, the centralized unit (CU) control plane that does not require high real-time performance is deployed on the geosynchronous earth orbit satellite, while the CU-user plane and the distributed unit that require low delay and high capacity are deployed on the low earth orbit (LEO) satellite closer to user equipment (UE). The proposed architecture cooperates with the conventional terrestrial communication system to provide large-coverage and high-reliability services for UE. In addition, four mobility management scenarios of the proposed cooperative two-layer satellite network architecture are investigated. And for each scenario, a corresponding handover approach is proposed to ensure the continuity of UE services, and the corresponding signaling overhead is analyzed. Results show that the proposed approach can greatly reduce the signaling overhead compared with the conventional scheme.