Successful GEO-to-LEO transition marks a significant step toward multi-orbit satellite connectivity for future 6G networks
Keysight Technologies and KT SAT announced that they have achieved what they say is the industry’s first NR-NTN (New Radio–Non-Terrestrial Network) handover between two different satellite orbits — shifting from a commercial geostationary (GEO) satellite to a simulated low-Earth orbit (LEO) link. The test was carried out at KT SAT’s Kumsan Satellite Network Operation Center and relied on a live Ku-band connection through the newly launched KOREASAT-6A.
The achievement marks an important milestone for the satellite industry, as it validates early behaviors of the 3GPP Release-19 Ku-band NTN standard—critical guidance for the next wave of global non-terrestrial deployments. By incorporating Ku-band operation into the handover test, the companies demonstrated how NR-NTN systems may perform when transitioning across orbital layers, an ability expected to underpin multi-orbit satellite networks spanning GEO, MEO and LEO.
Why Multi-Orbit Mobility Matters for 6G
Integrating satellite and terrestrial networks is increasingly viewed as essential for 6G. Yet satellite links come with engineering challenges—latency, Doppler effects and unstable signal conditions—that complicate mobility across space and ground domains.
The recent trial shows that these barriers can be overcome. By proving that a system can maintain service continuity while switching from GEO to LEO, Keysight and KT SAT demonstrated a foundational capability for building resilient, always-on connectivity—particularly important for remote, maritime and emergency communicationpeng environments.
Going Beyond Single-Orbit Demonstrations
Earlier NTN demonstrations primarily focused on GEO-only scenarios. This experiment moves further, validating continuous mobility across orbits. For KT SAT, this represents progress toward offering flexible multi-orbit communication services; for the ecosystem, it signals that multi-layer satellite networks are no longer theoretical.
The test also strengthens the technical basis for Ku-band NTN mobility, aligning closely with global operator planning for Release-19 frequency use.
Inside the Lab Trial
The demonstration used Keysight’s Network Emulator Solutions and UeSIM RAN Testing Toolset to simulate:
- base station behavior
- user equipment behavior
Engineers created a live two-way Ku-band link via KOREASAT-6A, then executed a handover from GEO to the emulated LEO link without losing service. Because the GEO link used Ku-band frequencies consistent with Release-19 NTN bands, the test produced insights directly applicable to early commercial system design.
Industry Impact: A Lower-Risk Path to Multi-Orbit Deployment
The controlled environment approach is designed to reduce reliance on costly field trials. Operators can model complex mobility scenarios before real constellations are deployed; device and chipset vendors can validate NTN performance earlier in development.
This improves:
- time-to-trial for emerging NTN solutions
- interoperability readiness across vendors
- confidence in scaling multi-orbit systems without prohibitive risk
According to the companies, the data generated will help shape standards discussions and operator strategies globally.
Industry Leaders Respond
KT SAT CEO Seo Young-soo highlighted the strategic value of the breakthrough:
“As the only satellite communications service provider in Korea, KT SAT is progressively validating the applicability of NTN gNB and UE using our five operational GEO satellites. Building on the results of this trial, we will actively explore strengthening the competitiveness of our next-generation GEO satellite for the global market and delivering integrated multi-orbit communication services based on NTN systems, including traffic handover across our own GEO and future LEO/MEO constellations.”
Keysight’s Wireless Test Group Vice President Peng Cao emphasized the benefits of emulation-based testing:
“This demonstration shows how emulation can bring future multi-orbit networks into the lab today. By combining a live GEO connection with emulated LEO conditions using NR-NTN parameters in Ku-band, Keysight gives operators and vendors a practical way to study NTN handover behavior, optimize mobility strategies, and reduce the cost and risk of early deployments.”
Toward a Multi-Layer, 6G-Ready Satellite Ecosystem
The successful trial positions KT SAT to advance toward a multi-layer satellite service portfolio that blends the stability of GEO platforms with the lower latency and agility of LEO systems. As 6G research accelerates, both companies expect multi-orbit NTN architecture to become a core component of next-generation communication networks.
With this demonstration, operators gain a clearer roadmap for integrating satellite and terrestrial domains—a capability increasingly viewed as fundamental to global 6G infrastructure.
