Efficient MIPv6 Vertical Handover in Satellite-Terrestrial Networks using Multicast Binding Update

The 6G vision for seamless global connectivity requires integrating Terrestrial Networks (TN) with NonTerrestrial Networks (NTN) to address the coverage limitations of traditional cellular systems. Vertical handover (VHO) in such dynamic TN-NTN environments demands robust IPlayer mobility management to ensure session continuity across heterogeneous networks. Mobile IPv6 (MIPv6) is a promising solution due to its ability to maintain session continuity through Home Address (HoA) and Care-of Address (CoA) mechanisms and support route optimization for efficient internet communication. However, standard MIPv6 struggles with high signaling overhead and unreliable binding updates in TN-NTN scenarios with frequent handovers and multiple Correspondent Nodes (CNs). To overcome these limitations, this paper proposes a novel MIPv6 enhancement leveraging a Smart Gateway (SG)-based multicast Binding Update (BU) mechanism. Unlike conventional MIPv6’s unicast BU approach, our mechanism features an SG that orchestrates optimized multicast BU transmission. This approach significantly reduces signaling overhead and enhances reliability over bandwidth-constrained NTN links, which are prone to interference, packet loss, and delay jitter. The proposed mechanism introduces a streamlined BU message format and a robust interaction process with reliability assurance, adhering to the Control and User Plane Separation principle. Simulations using ns-3 demonstrate that standard MIPv6 significantly reduces handover interruption time compared to baseline methods, and our multicast BU mechanism further improves interruption time, signaling overhead, and throughput stability. This innovative solution provides a scalable and efficient mobility management framework, advancing 6G satellite-terrestrial integrated networks.