Accelerating Handover in Mobile Satellite Network

TL;DR

This paper introduces a novel handover scheme for LEO satellite networks that leverages satellite trajectory predictability to significantly reduce latency, enhancing performance for latency-sensitive applications in 5G and 6G.

Contribution

The paper proposes a new handover flowchart and synchronized algorithm that utilize satellite trajectory information to minimize interaction delays and computational complexity in mobile satellite networks.

Findings

Handover latency is significantly reduced compared to existing schemes.

The proposed scheme outperforms 3GPP NTN and other methods in experiments.

Prototype implementation demonstrates practical feasibility and effectiveness.

Abstract

The construction of Low Earth Orbit (LEO) satellite constellations has recently spurred tremendous attention from academia and industry. 5G and 6G standards have specified LEO satellite network as a key component of 5G and 6G networks. However, ground terminals experience frequent, high-latency handover incurred by satellites' fast travelling speed, which deteriorates the performance of latency-sensitive applications. To address this challenge, we propose a novel handover flowchart for mobile satellite networks, which can considerably reduce the handover latency. The innovation behind this scheme is to mitigate the interaction between the access and core networks that occupy the majority of time overhead by leveraging the predictable travelling trajectory and spatial distribution inherent in mobile satellite networks. Specifically, we design a fine-grained synchronized algorithm to address the synchronization problem due to the lack of control signalling delivery between the access and core networks. Moreover, we minimize the computational complexity of the core network using information such as the satellite access strategy and unique spatial distribution, which is caused by frequent prediction operations. We have built a prototype for a mobile satellite network using modified Open5GS and UERANSIM, which is driven by actual LEO satellite constellations such as Starlink and Kuiper. We have conducted extensive experiments, and the results demonstrate that our proposed handover scheme can considerably reduce the handover latency compared to the 3GPP Non-terrestrial Networks (NTN) and two other existing handover schemes.