Advanced 5G Non-Terrestrial Network Mobility

The push to democratize wireless communications through space and provide Internet access to half of Earth’s population poses technical and business challenges demanding industry transformation. The latest 3rd Generation Partnership Project (3GPP) Rel-17’s incorporation of non-terrestrial networks (NTN) continues to pressure the communications industry to convert this dream into a reality.

With plans to leverage airborne stations and high-altitude platforms (HAPs) such as uncrewed aerial vehicles (UAVs), balloons, or dirigibles, 5G NTN aims to complement terrestrial networks, ensuring global connectivity. With heightened reliability expectations, 5G NTN services adopt key features from terrestrial networks, leveraging 5G signaling fundamentals.

In this document, learn how Keysight's Sky-to-Lab solutions allow the recreation of all the possible permutations of NTN and Terrestrial Network (TN) scenarios involving multiple satellites, different orbital models, and channel models. The solutions also measure application-level performance (including energy consumption, protocol, RF, throughput, latency, etc.), in the lab, testing the robustness of mobility management strategies.

Mobility in Satellite Networks

Three types of satellite orbits support 5G NTN:

• geostationary orbit (GSO)
• medium Earth orbit (MEO)
• low Earth orbit (LEO)
   

Satellite orbits like GEO, MEO, and LEO support 5G NTN, each with distinct properties impacting coverage and latency. LEO satellites offer lower latency but require frequent handovers due to fast movement.

5G NTN's impact on mobility procedures necessitates addressing challenges related to satellite handovers, affecting service quality and UE battery drain. The seamless handover process involves synchronization between satellites and precise trajectory estimation.

Satellite-to-Satellite Handovers

Supporting 5G NTN involves addressing mobility challenges, especially concerning LEO satellite movement. Static UEs on the ground require handovers between satellites for connectivity, impacting real-time services and battery drain.

Rel-16 Conditional Handovers extension for NTN with additional Rel-17 conditions optimizes handover timing and minimizes power consumption, improving network efficiency.

Integrating Terrestrial and Non-Terrestrial Networks

Another critical aspect and differentiator of 5G NTN compared to previously existing technologies is the seamless integration with existing TN infrastructure, which unlocks major new opportunities and use cases that this application note will address:

• Public safety for critical communications
• 3D coverage
• Massive IoT

Summary

The complexity of mobility scenarios underscores the need for lab emulation to replicate conditions accurately. Integrating various instruments such as the UXM 5G network emulator, PROPSIM channel emulator, UeSIM UE emulator, and WaveJudge wireless analyzer, Keysight's sky-to-lab test solutions enable end-to-end NTN emulation, covering multiple satellites and channel models. This solution assesses mobility management strategies, functional and performance metrics, and device robustness.

Read this application note to learn how to ensure multi-satellite NTN – terrestrial network mobility.