SDN-controlled open RAN X-haul with point-to-multipoint transceivers on a horseshoe network

Open RAN (O-RAN) is an architectural framework for 5G and beyond that enables an open, interoperable RAN infrastructure, with the centralized unit handling higher-layer functions and mobility management, and the distributed unit (DU) managing real-time, lower-layer operations near the radio units. Due to its inherently hub-and-spoke architecture, O-RAN is well suited for integrating point-to-multipoint (P2MP) coherent transceivers, enabled by digital subcarrier multiplexing (DSCM), to improve efficiency and reduce costs. On the other hand, the shift toward network disaggregation, driven by software-defined networking, promotes interoperability and automation. However, the control of commercially available P2MP transceivers remains proprietary, highlighting the need for open and standardized management frameworks. Therefore, we first propose an augmentation of the OpenConfig YANG data model for terminal devices to control DSCM and coherent P2MP transceivers. An experimental demonstration is shown in an integrated data and control plane testbed. Then, the first experimental implementation of Open RAN X-haul using P2MP transceivers on horseshoe optical networks is reported. 5G DU and P2MP leaf transceivers are dynamically activated according to cell traffic conditions to optimize energy efficiency.