5G NTN satellite testing

Satellite RF node testing

3GPP specification TS 38.108 establishes the minimum RF characteristics and minimum performance requirements of NR Satellite Access Nodes (SAN) in 5G networks. It ensures that SANs meet the necessary standards for reliable and efficient communication over satellite links, defining parameters such as transmit power, receiver sensitivity, frequency range, modulation schemes and channel bandwidths.

RF conformance testing scenarios for satellite access nodes are defined in specification TS 38.181. This specification can be considered the “satellite” counterpart to the well-known base station RF conformance testing specification TS 38.141.

Tests can be executed either as conducted or as non-conducted over-the-air (OTA) tests, depending on the SAN category. Similar to base station RF testing, SAN RF testing covers transmitter testing, receiver sensitivity testing and receiver performance testing. 3GPP defines fixed reference channels (FRC) to ensure reproducibility and comparability.

Characterizing phased array antennas

Phased array antennas (PAA) are crucial for the convergence of NTN with terrestrial networks. As NTN advances, the industry must address challenges such as incorporating satellite capabilities in telecom networks and developing advanced PAAs. These antennas play a key role in enabling seamless connectivity between terrestrial and NTN components.

PAAs are quickly reconfigurable and adapt more flexibly to actual throughput needs. Other benefits include:

• Higher signal-to-noise ratio
• High gain for long-distance and reliable communications
• Modular and scalable architectures
• Increased beam agility for efficient tracking
• Digital beamforming for multiple services and interference mitigation
• Longer lifespan

Traditionally, the low-noise amplifier (LNA) and radiating elements were individually characterized. However, the shift toward integrated antennas makes this separation impossible; the radiating element and the amplifier must be tested as a single unit. This involves:

• Calibrating the integrated antenna elements
• Testing for phase coherency between antenna elements
• Identifying faulty array elements using the method of equivalent surface current densities
• Verifying beam steering capabilities and testing for radiated power

Master your satellite infrastructure testing challenges

Testing 5G NTN satellite infrastructure poses three key challenges:

• Increased complexity
• Challenging signal propagation conditions
• Efficient and seamless synchronization of NTN and terrestrial infrastructure

NTN signal propagation conditions involve long distances between satellites and ground stations, resulting in inherent latency. Furthermore, varying atmospheric conditions; noise; interference from other signals and services; and intermodulation can degrade the signal.

Achieving seamless interplay and synchronization between NTN and terrestrial networks poses a complex challenge, demanding sophisticated conformance testing to guarantee optimal interoperability and performance.

High-performance solutions for 5G NTN satellite testing

Rohde & Schwarz offers smart test and measurement solutions that guarantee exceptional performance and reliability at every stage - from testing subsystems and components to verifying the performance of in-orbit service.

Browse our portfolio and discover:

• Signal generators and signal analyzers that can be equipped with the options required for testing satellite applications, including in-depth 5G physical layer signal generation and analysis
• CATR-based OTA chambers that provide the ideal environment for testing 5G FR2 antennas