Their integrated solution for the conformance testing of O-RAN Radio Units (O-RUs) was presented at the recent O-RAN ALLIANCE Global PlugFest Fall 2023, hosted at the i14y Lab in Berlin – supported by Deutsche Telekom and EANTC and i14y consortium partners. They verified Analog Devices’ 8T8R O-RU reference design according to both O-RAN and 3GPP pre-conformance specifications.
Network disaggregation requires interoperability between Open RAN network equipment provided by different vendors, according to Rohde & Schwarz. O-RUs need to conform with both 3GPP standards and O-RAN specifications. Fronthaul conformance tests, as defined by the O-RAN ALLIANCE, verify the proper behaviour of fronthaul interfaces and ensure that the O-RU designs are interoperable with the O-RAN distributed unit (O-DU).
Rohde & Schwarz and VIAVI Solutions are active in wireless communication testing and specifications development in the O-RAN ALLIANCE and 3GPP. They have developed an O-RAN conformance test solution supporting several Open Testing and Integration Centers.
To address multiple applications, technology company Analog Devices Inc (ADI) has developed a flexible O-RU reference design, noted Rohde & Schwarz. The ADI Kerberos O-RU 8T8R O-RU reference design and development kit supports time division duplex and frequency division duplex modes up to eight carriers (8CC) for all FR1 bands from 600 MHz up to 6 GHz. In addition, it includes a O-RAN Split 7.2 x both for 4G and 5G NR standards.
The test setup used at O-RAN PlugFest included the R&S SMM100A vector signal generator and R&S FSVA3000 signal and spectrum analyser from Rohde & Schwarz. They emulated a real-world radio environment by generating, capturing and analysing RF signals. For in-depth debugging, R&S VSE vector signal explorer analysis software was used for detailed measurement results.
A TM500 O-RU Tester from VIAVI Solutions implemented the O-DU side of the M-plane and C/U-plane functionality, necessary for interface configuration with the O-RU and to exchange I/Q data over the Open Fronthaul. Its O-RU Test Manager application provided a single point of control for the integrated system and ensured a “seamless, fully automated user experience” throughout the test setup.
This test platform evaluated various aspects of the ADI O-RU, including its behaviour, adherence to protocol standards and compatibility with O-RAN ALLIANCE guidelines. It included the control and user plane (CU-Plane) for both FDD and TDD modes of operation. In addition, the setup supported test cases from 3GPP TS 38.141-1 Base Stations conducted conformance transceiver testing.