Ku-Band NTN Handover Across Satellite Orbits

Keysight Technologies and KT SAT have demonstrated a non-terrestrial network handover between geostationary and low Earth orbit links using a live Ku-band satellite connection, validating standardized NTN mobility behavior in a controlled test environment.

Demonstrating multi-orbit NTN mobility
The demonstration was conducted at KT SAT’s Kumsan Satellite Network Operation Center in Korea using the KOREASAT-6A geostationary satellite. In a laboratory setting, the companies established what they describe as the first NR-NTN multi-orbit handover between a commercial GEO satellite and an emulated LEO link.

Unlike earlier NTN demonstrations limited to single-orbit connectivity, this scenario focused on maintaining service continuity as connectivity transitioned across orbital regimes. The handover was executed over a live Ku-band GEO connection, operating at approximately 12.3 GHz downlink and 14.4 GHz uplink, while the LEO segment was emulated to reproduce representative propagation and mobility conditions.

Relevance of Ku-band and 3GPP Rel-19
The use of Ku-band is technically significant, as this frequency range is now included in the 3GPP Release 19 specifications for non-terrestrial networks. By validating NTN handover behavior in Ku-band, the demonstration aligns directly with spectrum bands under consideration for future commercial NTN deployments.

Operating in this band enables more accurate assessment of timing, propagation delay, and Doppler effects compared with lower-frequency satellite demonstrations, providing data that is relevant to both operators and equipment vendors planning Rel-19–compliant systems.

Addressing mobility challenges in satellite networks
Integrating satellite and terrestrial networks introduces challenges not typically encountered in ground-based mobility, including long round-trip delays, frequency shifts due to satellite motion, and rapidly changing link conditions. These factors complicate handover procedures, particularly when transitioning between different orbital layers.

The demonstrated GEO-to-LEO handover shows how these effects can be managed within a standardized NR-NTN framework, supporting continuous connectivity rather than isolated point-to-point satellite links. This approach is intended to enable resilient coverage across remote or infrastructure-limited regions and in disaster-affected scenarios.

Test methodology and emulation environment
Keysight’s Network Emulator Solutions and UE-SIM RAN Testing Toolset were used to emulate both the base station and user equipment. A two-way communication link was established through the live GEO satellite, while the LEO connection was emulated to reproduce realistic orbital dynamics.

This setup allowed the teams to observe service continuity during handover without requiring simultaneous access to multiple physical satellites. Such lab-based validation enables operators to explore complex NTN mobility scenarios earlier in the development cycle, reducing dependence on costly and logistically complex field trials.

Implications for operators and the NTN ecosystem
For KT SAT, the results support the transition from single-orbit satellite services toward continuous, multi-orbit mobility, expanding potential service offerings across space and ground domains. For device, chipset, and infrastructure vendors, the approach provides a practical path to validate interoperability and mobility behavior ahead of large-scale deployment.

More broadly, the work contributes technical insights into Ku-band NTN mobility that can inform operator evaluations and standards discussions. By shortening time-to-trial and reducing technical uncertainty, such demonstrations are intended to help de-risk the commercialization of next-generation non-terrestrial networks as the industry moves toward 6G-era architectures.