Keysight Technologies and South Korea’s KT SAT have carried out what they describe as the industry’s first successful handover between satellites operating in different orbits, a step that highlights how next-generation mobile networks could integrate space-based and terrestrial connectivity.
In a laboratory-based proof of concept, the two companies demonstrated session continuity as a live connection was handed over from a geostationary Earth orbit satellite to an emulated Low Earth Orbit link. The test was conducted using KT SAT’s KOREASAT-6A satellite from its Kumsan Satellite Network Operation Centre.
The demonstration used a live Ku-band geostationary link, operating at downlink frequencies of around 12.3 GHz and uplink frequencies of around 14.4 GHz, combined with an emulated low Earth orbit environment. The companies said the test validated non-terrestrial network mobility in Ku band, which has recently been standardised under 3GPP Release 19 and is expected to play a central role in future satellite-enabled mobile services.
As the telecoms industry looks beyond 5G towards 6G, operators are seeking ways to combine satellites with terrestrial networks to provide continuous coverage, particularly in remote regions or during natural disasters. However, satellite communications bring additional complexity, including higher latency, Doppler effects, and rapidly changing link conditions, all of which make seamless handover more difficult.
Until now, most demonstrations have focused on single-orbit satellite connectivity. By showing a handover between different orbital regimes, Keysight and KT SAT aim to illustrate how satellite operators could evolve from point-to-point links towards continuous, multi-orbit mobility, potentially enabling more resilient, always-on services.
The test relied on Keysight’s network emulation tools to simulate both the radio access network and user equipment. A two-way connection was established via the live geostationary satellite, and service continuity was maintained as traffic was transferred to the emulated low Earth orbit link. According to the companies, running the test in Ku band allows the results to map directly onto frequency bands now under consideration for commercial deployment, giving operators and equipment makers earlier insight into real-world propagation and timing behaviour.
KT SAT said the approach would allow it to evaluate advanced mobility scenarios in the laboratory, before new satellites or compatible user devices are widely available, helping to reduce development costs and speed up service launches. The companies added that the work could also reduce reliance on expensive field trials for device and chipset vendors.
Seo Young-soo, CEO of KT SAT, said the company was using its fleet of five operational geostationary satellites to validate non-terrestrial network base stations and devices. He said the results would support plans to strengthen the competitiveness of KT SAT’s next-generation satellites and to develop integrated services spanning geostationary, medium, and low Earth orbit systems.
Peng Cao, Vice President and General Manager of Keysight’s Wireless Test Group, said the demonstration showed how emulation could bring future multi-orbit networks into the laboratory today, allowing operators and vendors to study handover behaviour and reduce the cost and risk associated with early deployments.
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