App-Notes » 5G NTN Signaling Testers: CMX500 Rohde & Schwarz Review

5G NTN Signaling Testers: CMX500 Rohde & Schwarz Review

Published on February 18, 2026

5g ntn cmx500 signaling tester rohde and schwarz test equipments

Introduction : The expansion of 5G into Non Terrestrial Networks (NTN) represents a paradigm shift in global connectivity. By utilizing Low Earth Orbit (LEO) and Geostationary (GEO) satellites, 5G can now reach remote maritime locations, rural deserts and disaster zones where ground based towers are non existent. However, testing devices for satellite communication is significantly more complex than testing for terrestrial 5G. Engineers must account for massive propagation delays, extreme Doppler shifts caused by satellites moving at thousands of miles per hour and complex handovers between rapidly moving orbital beams.

In the past, testing these variables required a “rack and stack” approach involving separate signal generators, channel emulators, and network simulators. The one box signaling tester integrates these functions into a single hardware unit

Product Spotlight: Rohde & Schwarz CMX500

The CMX500 is a leading example of an integrated signaling tester designed to handle the unique physics of space-based 5G. It acts as a “digital twin” of the sky, simulating the entire orbital environment within a laboratory setting.

Key Capabilities

  • Comprehensive Protocol Support: It handles NR-NTN (for 5G NR) and NB-NTN (for NTN NB-IoT chipsets) across diverse frequency bands, including sub-6 GHz and higher FR2 frequencies.
  • Integrated Channel Emulation: Dedicated internal FPGAs simulate real world impairments, such as variable path loss and atmospheric fading, without requiring external hardware.
  • Dynamic Orbit Simulation: Through tools like Constellation Insights, engineers can visualize satellite trajectories and analyze coverage gaps or beam to beam handovers in real time.
  • Direct to Cell (DTC) Validation: It includes specific test scenarios for Starlink style LTE DTC, measuring critical metrics like attach time, success rates, and recovery after a Radio Link Failure (RLF).
  • AI Powered Automation: Using the ScriptAssist tool, the CMX500 leverages AI to generate test scripts rapidly, reducing the time required to develop complex handover scenarios.

CMX500 is specifically engineered to solve the three pain points of NTN viz. Doppler Correction, Extended Timers and Ephemeris Data Handling.

Reference: Rohde & Schwarz Website for more information.

Comparative Guide : Other NTN Signaling Testers

While Rohde & Schwarz provides a highly integrated solution, other major manufacturers offer competitive NTN test platforms as mentioned in the table.

ManufacturerProduct with features
Keysight TechnologiesUXM 5G Network Emulator : A robust platform often used in conjunction with their PROPSIM channel emulators for massive MIMO and NTN fading simulations.
AnritsuMT8000A : A versatile signaling tester that supports both terrestrial and non-terrestrial 5G, known for its modular architecture and high frequency coverage.
Spirent CommunicationsWhile traditionally focused on channel emulation (Vertex), they provide integrated solutions for testing satellite to earth links and GNSS interference.
Viavi SolutionsTM500 : Widely used by network equipment manufacturers (NEMs) to stress test the capacity and signaling performance of satellite based base stations (gNodeBs).

Conclusion

As 5G NTN matures toward 6G, the ability to simulate the entire “earth to space” link in a single box is vital for reducing time to market. Tools like the Rohde & Schwarz CMX500 allow developers to iron out the complexities of orbital dynamics and protocol timing in a controlled environment, ensuring that when a device finally connects to a satellite, the link is as stable as a standard ground tower.