Secure and Efficient Group Handover Protocol in 5G Non-Terrestrial Networks

TL;DR

The paper tackles signaling storms and security risks in 5G NTN handovers by introducing a secure, efficient Xn-based group handover protocol that leverages additive threshold secret sharing and multiple Group Aggregators (GAs). An AMF-led grouping, GA-based aggregation, and group handover tickets coordinate handovers while reducing centralized load and protecting against compromised members. A custom discrete-event simulator in SimPy validates the approach, showing higher handover success rates and lower message overhead than baseline 5G handover, with open-source availability. The work delivers a practical NTN handover solution and highlights directions for formal security verification, multi-cell scenarios, and further reductions in signaling in ultra-dense deployments.

Abstract

The growing low-Earth orbit (LEO) satellite constellations have become an essential part of the fifth-generation (5G) non-terrestrial network (NTN) market. These satellites can enable direct-to-cell connectivity for mobile devices and support various applications with ubiquitous coverage for 5G and beyond networks. However, satellite-based NTNs bring several challenges to the 5G handover protocol design. The high mobility of satellites can lead to signaling storms and security compromises during handovers. This paper addresses these challenges by proposing a secure and efficient group handover protocol. The protocol's effectiveness is evaluated on a custom discrete-event simulator and compared against the baseline 5G handover scheme. The simulator is made publicly available.

Figures (5)

• Figure 1: Handover scenario with Earth moving cells
• Figure 2: Sequence diagram of the proposed NTN handover protocol (the symbol $\Diamond$ indicates a communication channel is secure; symmetric encryption with a key $K$ is denoted $(*)_K$)
• Figure 3: Message processing model
• Figure 4: Scenario of our experiment
• Figure 5: Message count every 200 ms