Experimental Evaluation of Multi-Vendor 5G Open RANs: Promises, Challenges, and Lessons Learned

Open Radio Access Network (Open RAN) is a new paradigm shift envisaged for the future RAN, which is composed of disaggregated and virtualised RAN functions that are interconnected via open interfaces, and can be configured to optimise network performance via intelligent closed-loop control. To progress the development of an open, multi-vendor, and reconfigurable RAN, the existing design and deployment approaches need to be revisited. This paper presents the recent endeavours from SmartRAN Open Network Interoperability Centre (SONIC) Labs to integrate and assess the interoperability and functionality of O-RAN-based multi-vendor Open RAN solutions on SONIC Labs commercially-neutral, multi-tenancy open network testbed. The viability of creating multi-vendor Open RANs is assessed according to the O-RAN-compliant Interoperability Testing (IOT) and End-to-End (E2E) test suite. The test campaigns confirm the E2E integration and successful IOT between pairs of Open RAN components for 22 multi-vendor Open RANs. In this paper, we elaborate on the lessons learned during the integration attempts and testing of the Open RANs, highlight the key findings from the analysis of the results, and provide recommendations from the observations. The findings presented in this paper help to pave the way towards accelerating the enhancements needed for improving the maturity of the Open RAN products, and can play an important role in development of open, modular, and (ideally) plug-and-play solutions.