Enabling realistic experimentation of disaggregated RAN: Design, implementation, and validation of a modular multi-split eNodeB

Abstract

Software-defined networking and network function virtualization are the key enablers in the division of base station functionalities and the deployment of some of these in central nodes. In this way, eNodeB tasks, traditionally deployed at dedicated nodes, are distributed between Central Units (CU) and Distributed Units (DU), which are closer to the Radio Units (RU). The 3GPP has specified eight possible functional splits between the CU and the DU. Despite their importance, to date, there is a lack of practical approaches that enable the real separation of multiple functional splits into different nodes, which would in turn enable the adaptation of the functional split configuration, according to network conditions and traffic load. This paper presents the design and implementation of an experimental architecture that allows the actual separation of protocol layers into different nodes, enabling the experimentation with up to four functional split configurations. The validation results demonstrate the feasibility of the proposed implementation, which copes with the delay requirements established by the Small Cell Forum in all configurations.