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.
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.
By following the VIAVI Test Journey through the test progression outlined, you can accelerate your product TTM.
- It can reduce or remove potential issues when integrating with other O-RAN network components, performance and efficiency in testing to name a few.
- 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.
- 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.
The O-RU Test Solution allows the testing of the O-RAN Radio Unit throughout the entire journey, allowing the simplification of testing and acceleration of product to market.
Simplify O-RU Conformance Testing - VIAVI has partnered with Rohde & Schwarz to provide an integrated solution for conformance testing of the O-RU O-RAN network component.
Conformance testing is a requisite according to O-RAN standards and must be done to ensure the proper operation of the O-RAN fronthaul interface, the management, synchronization, control and user planes.
This joint solution is designed to provide productivity improvements and efficiency in testing. The single point of control runs, configures, manages and generates test reports with an easy-to-use interface.
Proven in the spring 2022 O-RAN ALLIANCE Plugfest:
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.
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 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.
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.
- 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
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