FlexRAN

TLDR

The radio access network offers a promising opportunity for software‑defined networking, yet this potential remains largely untapped because no dedicated SD‑RAN platform exists. This work introduces FlexRAN, a flexible, programmable SD‑RAN platform that decouples control and data planes through a custom southbound API. FlexRAN, built as an extension of a modified OpenAirInterface LTE platform, employs virtualized control functions and delegation to provide a real‑time, coordinated, and programmable control plane that demonstrates feasibility under strict RAN timing constraints.

Abstract

Although the radio access network (RAN) part of mobile networks offers a significant opportunity for benefiting from the use of SDN ideas, this opportunity is largely untapped due to the lack of a software-defined RAN (SD-RAN) platform. We fill this void with FlexRAN, a flexible and programmable SD-RAN platform that separates the RAN control and data planes through a new, custom-tailored southbound API. Aided by virtualized control functions and control delegation features, FlexRAN provides a flexible control plane designed with support for real-time RAN control applications, flexibility to realize various degrees of coordination among RAN infrastructure entities, and programmability to adapt control over time and easier evolution to the future following SDN/NFV principles. We implement FlexRAN as an extension to a modified version of the OpenAirInterface LTE platform, with evaluation results indicating the feasibility of using FlexRAN under the stringent time constraints posed by the RAN. To demonstrate the effectiveness of FlexRAN as an SD-RAN platform and highlight its applicability for a diverse set of use cases, we present three network services deployed over FlexRAN focusing on interference management, mobile edge computing and RAN sharing.