Keysight and KT SAT claim satellite first with GEO to LEO link

Keysight Technologies and KT SAT have revealed a live multi-orbit proof-of-concept demonstration, showcasing session continuity from a geostationary Earth orbit (GEO) to an emulated low Earth orbit (LEO) link, thereby validating a core advanced communications capability.

Explaining the rationale for their move, the companies said that as the industry moves towards 6G, integrating satellite and terrestrial networks is essential to deliver continuous coverage and resilient service in remote or disaster-affected areas. Yet multi-orbit mobility has always been one of the toughest engineering hurdles to surmount in satellite communications due to long delays, Doppler effects and unstable satellite links.

The collaboration is said to create a dependable way to study real non-terrestrial network (NTN) behaviour before large satellite constellations are deployed.

By incorporating Ku‑band operation into this multi-orbit mobility scenario, Keysight and KT SAT believe they have validated NTN behaviours in a frequency range now central to emerging global standards and operator deployment strategies. And by moving beyond earlier demonstrations focused on single-orbit GEO connectivity, the organisations said they have shown how operators can evolve from point-to-point satellite links to continuous multi-orbit mobility, while also establishing an important technical milestone in advancing Ku-band NTN mobility.

In practical terms, Keysight said it has demonstrated an NTN handover using the KOREASAT-6A satellite at KT SAT’s Kumsan satellite network operation centre in Korea.

In a controlled lab environment, the companies said they have established the industry’s first NR-NTN multi-orbit handover between a commercial GEO satellite and an emulated LEO link. The demonstration was performed over a live Ku‑band GEO connection – downlink around 12.3GHz and uplink around 14.4GHz – marking, said the two companies, a major milestone towards testing the newly standardised 3GPP Rel‑19 Ku‑band NTN spectrum.

Using Keysight’s Network Emulator Solutions and UeSIM RAN Testing Toolset, the teams emulated the base station and user equipment, established a two-way link through KOREASAT-6A, and maintained service continuity during a handover from GEO to an emulated LEO connection.

Operating the GEO link in Ku‑band is said to ensure that these mobility insights directly map to the Rel‑19 NTN frequency bands now entering commercial planning, giving operators and device suppliers earlier visibility into real‑world propagation, timing and interoperability behaviours. As a result, KT SAT said it can now explore and validate advanced NTN mobility scenarios in the lab, before satellites or user devices are widely deployed, accelerating its roadmap and reducing the time and cost of bringing new multi-orbit services to market. 

In addition, the firms claimed that their collaboration shows how operators can extend coverage and resilience, while device and chipset suppliers gain a lab-based path to validate NTN mobility without relying solely on expensive field trials. Insights from this work are also intended to inform standards discussions and operator evaluations, helping the ecosystem shorten time-to-trial and de-risk commercialisation.

“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,” said KT SAT CEO Seo Young-soo.

“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.”

Peng Cao, vice-president and general manager of Keysight’s wireless test group, added: “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 behaviour, optimise mobility strategies, and reduce the cost and risk of early deployments.”