VIAVI TM500 O-RU Tester for O-RAN Radio Unit Conformance, Functional and Performance Testing

The VIAVI TM500 O-RU Tester is a joint VIAVI and Rohde & Schwarz solution for validating O-RAN Radio Units (O-RUs). The O-RU is the disaggregated O-RAN network element that performs the lower physical layer and RF functions and connects to the O-RAN distributed unit (O-DU) over the standardized O-RAN fronthaul interface, processing high sampling rate IQ data in real time.

The tester covers the O-RU development lifecycle from functional testing through conformance (certification) to performance testing. It emulates the O-DU and generates the Open RAN C/U-plane messaging for the IQ data stream in real time, with configurable test parameters across a wide range of frequencies and bandwidths.

Test modes

Conformance Test Mode provides test cases compliant with O-RAN WG4 and 3GPP specifications. Functional Test Mode lets users build their own test campaigns from built-in test case templates. Performance Test Mode supports customizable real-world scenarios using real-time signals from TM500 UE emulation.

Test setups

Two main setups are offered. The VSA/VSG setup uses a standalone Rohde & Schwarz vector signal analyzer and vector signal generator and is aimed primarily at conformance and certification testing. The PVT360A setup uses a compact single-box VSA/VSG instrument and is aimed at early-stage functional and system-level development, with multi-port testing and scaling from single-generator to multi-generator configurations. An NGP power meter setup adds energy savings and energy efficiency testing.

Direct Performance Testing

Beyond O-RAN conformance, the O-RU can be tested with an emulated O-DU over the 3GPP stack (Direct Performance Testing), checking that 3GPP U-plane data is decoded correctly before integration with a real O-DU and end-to-end testing. The tester works with the TM500 and the TeraVM Core Emulator for end-to-end and capacity testing.