5G NTN satellite testing

5G NTN satellite testing

Solutions for testing non-terrestrial networks

Transparent and regenerative NTN payload testing

A transparent satellite acts as a remote radio unit with the gateway, while the 5G NR base station (gNB) intelligence remains ground-based. This setup is commonly used for backhaul via the satellite network or temporary 5G networks, with the satellite serving as a repeater for the 5G signal.

In contrast, a satellite with a regenerative payload can host gNB functions, either fully or partially. The 5G base transceiver station can be split into a centralized unit (CU) and a distributed unit (DU), with different models supporting configurations such as incorporating both the DU and CU in the satellite or hosting DU functions in the satellite while the CU remains terrestrial-based.

Satellite payload testing has various aspects, such as:

  • Group delay measurements to determine phase distortions and characterize the transmission path quality
  • Characterization of satellite transponders with measurements such as gain compression, AM/AM, AM/PM and distortion NPR/ACLR
  • Noise power ratio (NPR) measurements to test the linearity of an RF transponder and simulate a Gaussian noise-like distribution of a multi-channel communications payload
  • Modulation accuracy and bit error rate (BER) measurements to verify the quality of satellite links during satellite integration and in-orbit operation
  • Searching for spurious emissions
  • Noise figure and gain measurements

Due to the interplay of NTN and terrestrial networks, NTN payload testing must account for the following:

  • Stronger Doppler effect due to high satellite speeds
  • Low signal-to-interference-plus-noise ratio (SINR)
  • Combination of terrestrial and atmospheric fading profiles
  • High crest factor in OFDM waveforms

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

Benefits of our satellite infrastructure testing solutions

Our products are compatible with the latest satellite standards and offer comprehensive test capabilities, including RF, protocol, end-to-end application and signaling analysis. They are also modular, allowing for scalability, customization and expansion to meet specific testing requirements and keep up with emerging wireless technologies.

Other benefits include:

  • Faster time-to-market
  • Improved product quality
  • Ensured compliance with industry standards and specifications
  • Quick and early detection of design flaws

If you have any questions please contact us

Products for 5G NTN satellite testing

FSW signal and spectrum analyzer

The R&S®FSW offers an analysis bandwidth of up to 8.3 GHz for measuring wideband-modulated or frequency agile signals like those used in the new 5G NR standard. It can measure multiple standards simultaneously for quick and easy error detection.

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SMW200A vector signal generator

The R&S®SMW200A is the signal generator for the most demanding applications. It is ideal for generating digitally modulated signals that are required for developing new wideband communications systems and verifying 4G and 5G base stations.

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ATS1800C compact OTA chamber

R&S®ATS1800C compact 3GPP compliant and transportable CATR test chamber for testing 5G phased array antennas, modules and devices over the air (OTA) from R&D to conformance.

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5G NTN satellite testing Knowledge+

Webinar: 5G Non-terrestrial networks - technology update

In this webinar, we take a closer look at the current status of how non-terrestrial networks are treated in the 3GPP standardization, especially in Rel. 17: what the technical challenges are, how the spectrum allocation look like, and how to leverage the deployment of NTN capable devices and networks.

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Webinar: The road ahead for satellite based Non-Terrestrial Networks (NTN)

In this webinar, experts from Rohde & Schwarz and GateHouse will take a closer look at the current status of how non-terrestrial networks are treated in the 3GPP standardization, especially in Rel. 17.

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Satellite Industry Days Part 2: Taking next steps on non-terrestrial networks and satellite 5G/IoT

Explore non-terrestrial networks (NTN), the emerging market for high-rate data internet and globally available communication services, expanding global coverage and bridging the digital divide.

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White paper: 5G NTN takes flight

This white paper aims to provide you with an overview of the major aspects of the technology and corresponding challenges. We have tried to incorporate the latest state of the technology involved, representing the current status of the standardization work ongoing in 3GPP.

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