5G NR NTN Satellite Connectivity

This video demonstrates how to configure and run a laboratory test of 5G NR non-terrestrial network (NTN) satellite connectivity using Keysight’s UXM 5G test platform and UE emulation. Combining an introduction to NTN concepts with a practical setup walkthrough and live demonstration, it shows how satellite movement, propagation delay, Doppler shift, and changing coverage affect a mobile device’s connection to an emulated satellite network.

The first section introduces different approaches to satellite-based cellular connectivity, distinguishing direct-to-cell services for unmodified devices from 3GPP-based narrowband IoT NTN and NR NTN. The discussion focuses on NR NTN, also called 5G NTN, and its potential to support higher-data-rate applications such as voice, video calling, and video streaming. It then explains transparent, or bent-pipe, satellite architecture and regenerative architecture. In the transparent arrangement, the base station remains on the ground, with a feeder link to the satellite and a service link to the mobile device. In the regenerative arrangement, base station processing resides on the satellite.

The video discusses L-band and S-band operation, including NR bands n255 and n256, and compares geosynchronous satellites with low Earth orbit (LEO) satellites. Lower satellite altitude brings different delay and path-loss characteristics, while rapid satellite movement creates limited visibility windows for a stationary device. These changing coverage conditions make transitions between satellite cells an important part of the test scenario.

Another key topic is the information a device needs to communicate over a satellite link. The presenter explains how System Information Block 19 (SIB19) supplies satellite information that helps the device account for satellite position and motion. Together with knowledge of its own location, the device uses this information to adjust transmission timing and compensate for delay and Doppler effects.

The configuration walkthrough uses two emulated satellite cells operating on the same frequency with different physical cell identities. The device location is configured in Barcelona, and the scenario uses band n255 with regenerative satellite architecture. Orbit files generated with a geometric channel modeling tool are loaded into the UXM’s internal orbit emulation engine. Each satellite provides approximately three minutes of visibility, with about 20 seconds of overlapping coverage between the two cells.

On the device side, a UE emulator represents one NR NTN mobile device. The presenter describes the protocol-processing and radio components, their cabled connection to the UXM, and the UE’s role in compensating for satellite-related delay and Doppler. A scenario-control tool initiates registration, connection establishment, and ongoing ping traffic.

In the live demonstration, the satellite cells are activated, the emulated UE synchronizes with the network, and the connection scenario is started. Monitoring displays show device and satellite positions, satellite movement, changing Doppler shift, propagation delay, throughput, and connection performance. As the first satellite moves out of coverage and the second becomes available, the connection transfers through a reestablishment process. The demonstration shows a temporary interruption followed by attachment to the second cell, rather than uninterrupted service.

The video gives wireless engineers a practical introduction to configuring an NR NTN test environment and observing device behavior under changing satellite conditions. It connects the underlying satellite communication concepts with the test setup, scenario execution, and monitoring needed to investigate connectivity and mobility between emulated LEO satellite cells.