Network disaggregation requires interoperability between Open RAN network equipment provided by different vendors. O-RAN radio units (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 behavior 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 both leading in wireless communication testing and active in specifications development in the O-RAN ALLIANCE and 3GPP. Together they have developed an O-RAN conformance test solution supporting several Open Testing and Integration Centers (OTIC).
O-RAN ALLIANCE Global PlugFests are periodic events organized and co-sponsored by O-RAN ALLIANCE to enable efficient progress of the O-RAN ecosystem through well-organized testing and integration. Vendors and providers come together to test, evaluate and verify their products and solutions. The O-RAN ALLIANCE Global PlugFest Fall 2023 was held in 16 labs across eight countries. One of these events was hosted at the i14y Lab in Berlin – supported by Deutsche Telekom and EANTC and i14y consortium partners. There, technology vendors like Analog Devices, had the opportunity to verify the conformance of their platforms with test and measurement solutions from Rohde & Schwarz and VIAVI Solutions amongst others.
To address multiple application scenarios, ADI has developed a particularly flexible O-RU reference design. The ADI Kerberos O-RU (ADRV9040-RD-RUMB) 8T8R O-RU reference design and development kit supports time division duplex (TDD) as well as frequency division duplex (FDD) modes up-to eight carriers (8CC) for all FR1 bands from 600 MHz up to 6 GHz. In addition, it includes a complete O-RAN Split 7.2 x both for 4G and 5G NR standards.
The setup used at the O-RAN PlugFest at the i14y Lab to validate ADI’s Kerberos O-RU consisted of the following test solutions:
- The R&S SMM100A vector signal generator and R&S FSVA3000 signal and spectrum analyzer from Rohde & Schwarz emulated a real-world radio environment by generating, capturing and analyzing RF signals. For in-depth debugging R&S VSE vector signal explorer analysis software was used allowing to access detailed measurement results.
- The TM500 O-RU Tester from VIAVI Solutions has implemented the O-DU side of the M-plane and C/U-plane functionality which was necessary for the configuration of the interface with the O-RU and to exchange I/Q data over the Open Fronthaul.
- The O-RU Test Manager application from VIAVI has provided a single point of control for the integrated system and has ensured a seamless, fully automated user experience throughout the test setup.
At the i14y Lab PlugFest, this test platform evaluated various facets of the ADI O-RU including its behavior, adherence to protocol standards, and compatibility with O-RAN ALLIANCE guidelines. This 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 (BS) conducted conformance transceiver testing. The tests were executed under following conditions:
- TDD: RF: 1×100 MHz CC; SCS: 30 kHz; Frequency band: DL/[email protected]
- FDD: RF: 1×20 MHz CC; SCS: 15 kHz; Frequency band: DL 2.64203GHz and UL: 5.52203 GHz
Rohde & Schwarz helps to drive development, deployment and operation of Open RAN networks with its wide portfolio ranging from mobile network infrastructure equipment verification through conformance to mobile network testing and benchmarking.
Alexander Pabst, Vice President of Market Segment Wireless Communications at Rohde & Schwarz, says: “Open RAN is having its moment now. Large O-RAN deployments are planned in several regions all around the world. Open RAN pioneers like ADI require sophisticated O-RU test solutions to verify the conformance and interoperability of their designs in a disaggregated multi-vendor network. The i14y Lab in Berlin is a fruitful collaboration space for testing, harmonizing and validating Open RAN solutions and we are proud to be a consortium partner of i14y Lab.”
Stephen Hire, Vice President of Wireless Marketing at VIAVI, says: “For network operators to gain confidence to deploy O-RAN equipment widely, they need to confirm that there are no interoperability issues, and that the performance of the radios is as good or better than traditional solutions. We are proud to have had the opportunity to work with our partners Rohde & Schwarz and i14y Lab to help verify the capabilities of the ADI reference design to enable them to achieve an important milestone in the commercialization of O-RAN technology”.
