TM500 O-RU Tester

A NITRO Wireless Product

Validate your O-RAN Radio Units and accelerate time to market - Delivering test solutions beyond traditional conformance validation

The O-RU is one of the disaggregated O-RAN network elements designed to perform the lower physical layer and RF functions. It interfaces with the O-RAN distributed unit (O-DU) over what is known as the standardized O-RAN fronthaul interface. The O-RU performs its operations in real-time, dealing with high sampling rate IQ data. Its smooth running is essential to the performance of the overall system.

5G RAN Solutions

O-RU Test Challenges

Validating the timing and synchronization

Validating the timing and synchronization between an emulated O-DU and O-RU. This is important as the timing ensures that all aspects of the management, control and user planes are synchronized and eliminates the risk of latencies or lost/dropped packets.

Ensuring inter-operation of the O-DU with different vendor O-RUs

Ensuring inter-operation of the O-DU with different vendor O-RUs, which are all supposed to operate according to the O-RAN standard. This sounds easy and is one of the key goals with Open-RAN architecture, but in practice, it comes with challenges. Different vendor O-RUs may have different delay profiles, different software implementations and a different performance, meaning they may not plug, play and operate correctly.

Guaranteeing the performance is as expected in a multi-vendor scenario

The latency, maximum throughput and handling of certain features, such as beamforming, may not produce the same performance between two different vendors. Due to the flexibility that the O-RAN standard encompasses, testing must address the complexity of using different vendor combinations while expecting consistent results.

Conformance testing is vital but it does not ensure that the O-RU can deliver the expected performance when 3GPP features are implemented before or after it has been integrated within the network.
O-RAN provides flexibility. It also means that the complexity in testing can increase owing to mixing O-RAN components from different vendors.

Simplifying the evaluation of the O-RU

The TM500 O-RU Tester goes beyond conformance specifications and provides the simplicity of evaluating the O-RU to enhance productivity for the customer and also provides advanced test methods that reduce the risk of the O-RU underperforming from an E2E point of view.

Test Journey

By following the VIAVI Test Journey through the test progression outlined, you can accelerate your product TTM.

  1. It can reduce or remove potential issues when integrating with other O-RAN network components, performance and efficiency in testing to name a few.
  2. It helps to avoid limitations in the performance of the O-RU. For example: achieving maximum throughput under different sub-carrier spacings, bandwidths and carrier aggregation scenarios.
  3. It ensures that not only the O-RAN fronthaul semantics and syntax work, but 3GPP U-plane data can successfully be decoded before any form of E2E testing where issues are more difficult to diagnose due to the O-RAN vendor diversity.

Conformance Testing

O-RU conformance, interoperability, and performance, including real-time generation of the O-RAN C/U-plane messaging for the IQ data stream

In partnership with Rohde & Schwarz

The TM500 O-RU Tester is designed with two versatile test setup modes to cater to a variety of testing requirements and budget constraints. Each setup mode is tailored to provide specific benefits and functionalities:

TM500 O-RU Tester with VSA/VSG Test Setup

  • High Precision: Utilizes a standalone Vector Signal Analyzer (VSA) and Vector Signal Generator (VSG) for broad capability signal analysis and generation, ideal for detailed performance assessment.
  • Flexibility: Offers the ability to test a wide range of frequencies and bandwidths, supporting diverse O-RU configurations and compliance testing needs.
  • Customizability: Adaptable to a variety of test scenarios, allowing users to configure and modify test parameters according to specific network demands.
  • Use Case: Best suited for R&D and lab environments where precision and flexibility in signal manipulation are critical.

TM500 O-RU Tester with PVT360A Test Setup

  • Integrated Solution: Incorporates the PVT360A, a compact, single-box VSA/VSG instrument that enhances test efficiency and reduces operational complexity.
  • High Throughput: Designed for rapid testing with capabilities for simultaneous multi-port testing, reducing test times significantly.
  • Scalability: Offers scalable options from basic single-generator setups to advanced configurations with multiple generators and analysers.
  • Use Case: Ideal for the earlier stages of development when multiple engineers must work in parallel to perform functional and system level testing and where speed, efficiency, and cost-effectiveness are paramount.

Why VIAVI and R&S:

  • Solution designed for scalability
  • Streamlined single control point for simplified usage
  • Singular support ownership post-sales through VIAVI
  • Compatible with TM500 for performance testing
  • Leverage VIAVI RANtoCore market dominance, rooted in the industry-leading TM500
  • Use R&S top-tier RF capabilities and market leadership

Direct Performance Testing (DPT)

Complimentary to conformance testing, this goes beyond the O-RAN standards to test at the 3GPP level. We call this Direct Performance Testing (DPT) where the O-RU is tested with an emulated O-DU over the 3GPP stack. The advantages of doing this are numerous and enables a much smoother integration with a real O-DU ahead of E2E testing.


Advantages of Direct Performance Testing (DPT)


  • Gets the best performance out of each O-RAN NW element prior to E2E testing
  • Brings efficiency gains ahead of integration with O-DU and E2E performance testing e.g. eliminates issues that E2E testing can mask.
  • Reduces "pointing the finger" culture e.g., elements from different vendors
  • Raises the profile of a vendor NW components e.g., the O-RU conformance test cannot guarantee that it will workover the 3GPP 5G stack.

End-to-end Testing

O-RU, O-DU and O-CU are tested in conjunction with a real or emulated core network. One of the aims is to obtain the best performance across all network components. This is a typical type of test that would be performed by a System Integrator or OTIC laboratory.

Watch a demonstration of end-to-end testing here:

Capacity Testing

Capacity testing scales the numbers of User Equipment devices (UEs), with carriers. This is a more realistic test that would emulate a real deployment. This type of test would ensure the best Quality of Service (QoS) for each user under different mobility and fading conditions.

O-RAN Alliance - Virtual Exhibition

Why choose the TM500 O-RU Tester

  • Simplify the testing of O-RUs across the whole test lifecycle
  • Accelerates TTM by resolving issues earlier in the development
  • Works seamlessly with the industry-standard TM500 and TeraVM Core Emulator
  • Re-uses a derivative of the TM500 and software, reducing risks of integration, providing quality, stability and ensuring most importantly that the inter-operability and performance test
  • Single point of control for, running, configuring and enhanced productivity
  • A mature & proven O-RAN CUSM interface ensures a smoother inter-operation with different vendor O-RUs while maintaining peak performance.
  • TM500 software ensures O-RAN tests and results are consistent and repeatable.

Key Features

  • NETCONF Client to support Start-Up and get/edit configuration of M-plane attributes in the O-RU under test
  • O-RAN C/U-plane functionality to  exchange I/Q data over Lower Layer Split 7-2x interface
  • Real time C/U-plane eCPRI packets generation
  • Embedded protocol analyzer for OFH traffic analysis
  • C/U-plane messaging support with eCPRI over Ethernet
  • PTP/SyncE Grandmaster + PTP  Client for Synchronization with external PTP Master
  • OFH interface connectivity monitoring
  • Wide range of synchronization topologies
  • Multiple options for stimulus waveform generation


  • Conformance Testing
  • Direct Performance Testing
  • End-to-end Testing
  • Capacity Testing
  • O-RAN Fronthaul Testing
  • 5G Physical Layer Testing

  • Repair and Calibration

    Our products live in rugged environments for over 10 years with 1000s of test connect/disconnect cycles.  We will be there to support you to ensure components that require maintenance like connectors, batteries, and software updates to ensure you are ready to test accurately for years to come. We apply factory procedures that use fast, automated calibration and functional verification, maintenance using OEM parts and the application of all engineering change orders and software updates. Services are available through contract Care plans, FleetCare or per incident as requests. 

    Top 4 Reasons to Choose VIAVI for Your Repair and Calibration Needs:

    • Minimize business disruption
    • Budget
    • Measurement Accuracy and Product Reliability
    • Measurement Compliance, TL9000 certification and OEM Standards

    Explore More

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