5G InterOPERAbility of Open RAN Components in Large Testbed Ecosystem: Towards 6G Flexibility

An Open Radio Access Network (Open RAN) is a mobile network architecture that allows a Mobile Network Operator (MNO) to use network components from different vendors thanks to open interfaces between components and virtualization of parts of the mobile network which are currently provided by specialized software and hardware. The Open RAN concept enables the flexible customization of mobile network architectures according to specific use cases or required Key Performance Indicators (KPIs). As the diversity of architecture component vendors further increases and innovations further accelerate with 6G, the interoperability of network elements needs to be guaranteed so as to ensure flexible 6G system configurations. This paper describes the interoperability aspects in Open RAN and gives an overview of the available 5G Open RAN testbed ecosystem which is provided by the French-German collaboration project 5G-OPERA. More specifically, three major testbeds are introduced in this paper: 1) The OpenAirInterface (OAI) testbed is an open-source project developing RAN, Core Network (CN), and RAN Intelligent Controller (RIC). 2) The 5G-Core testbed including traditional vendors and Open RAN solutions, currently complemented with open-source CNs. 3) The industrial testbed, which is the largest available Open RAN testbed for private networks in Germany. These testbeds enable the benchmarking of traditional and new vendors and thus provide an environment for examining the interoperability of network components from different vendors as well as particular component features. Moreover, Open RAN boosts innovations, such as network slicing and localization, which can be tested on the 5G-OPERA experimental platform. The insights provided in this paper into 5G testbeds can contribute to the foundations for building experimental platforms for examining the interoperability of future 6G system components.