Improving efficiency for base station interoperability testing

As part of an R&D project from Japan’s New Energy and Industrial Technology Development Organization (NEDO), NEC Corporation and Fujitsu are investigating technology for testing the interoperability of post-5G base stations compliant with O-RAN specifications. A connectivity testing environment using this technology was constructed at the companies’ laboratories, and tests were conducted over a two-year period.

Background

As digital transformation (DX) advances in various industries, fifth-generation mobile communications systems (5G) are being deployed globally as the infrastructure for DX. In the post-5G era, ultralow latency, massive simultaneous connectivity and other 5G functions will be further enhanced and become more widespread. This will lead to even lower power consumption and wider support for virtualisation of networks, further driving the expansion of the telecommunications infrastructure market, including the replacement of existing base station equipment.

To provide customers with higher-quality communication services, operators are increasingly choosing the most suitable base station equipment from a variety of vendors for use in their own networks. In response, the O-RAN Alliance — an industry group composed of telecommunications carriers and manufacturers from around the world — has promoted standardisation for connections between multiple base station devices and has formulated conditions for connecting base stations from different vendors. However, testing the operability of connected devices is time-consuming because it must be performed by the operator, and an even longer time is required if retesting must be conducted to resolve defects. This, therefore, hinders the deployment of equipment conforming to O-RAN specifications.

To address this problem, NEC and Fujitsu have established test environments in the UK and North America, which are foreseen as upcoming O-RAN markets, as part of the NEDO project. From August 2021 to June 2023, NEC’s UK laboratories and Fujitsu’s US laboratories conducted operational testing using a combination of profiles and base station equipment vendors used by various international operators in actual commercial environments in efforts to develop a technology that streamlines the process and shortens the time required to verify interoperability.

Results of the joint efforts

NEC and Fujitsu jointly developed a technology to automate the testing of interoperability between base station equipment from various vendors at the O-RAN fronthaul. They have enhanced the functionality to support the actual connection conditions used by operators in different countries and regions. This technology includes proprietary technologies such as the FrontHaul Analyzer (FHA), which connects base station equipment to verify fronthaul protocol; the Pseudo-DU (P-DU), which performs unit testing of radio units (RU); a test scenario extraction tool that automates each verification process; a test parameter modification tool; and a test result assessment tool.

Interoperability at the O-RAN fronthaul was tested using multiple combinations of base station equipment from different vendors and operating conditions, assuming actual commercial environments of telecommunications carriers (operators) in Europe and North America at the two companies’ laboratories in the UK and the US. Automation of testing using the technology developed through the project reduced testing time by more than 30% compared with conventional manual testing.

Reducing the interoperability testing time will enable operators to shorten the lead time for deploying systems that combine O-RAN compliant base station equipment from different vendors. This will contribute to the advancement of open configurations in 5G networks currently in widespread use, as well as the construction of new networks in anticipation of future post-5G deployments.

Future plans

Going forward, NEC and Fujitsu will further utilise the technology developed through this project for joint testing with operators and base station equipment vendors in Japan and internationally, in order to shorten the time required to deploy O-RAN compliant equipment. By doing so, they aim to contribute to the revitalisation of the telecommunications infrastructure market by supporting the global spread and development of open 5G networks.

Image credit: iStock.com/Bill Oxford