RAN Intelligent Controllers (RICs) are programmable platforms that enable data-driven closed-loop control in the O-RAN architecture. They collect telemetry and data from the RAN, process it in custom applications, and enforce control or new configurations on the RAN. Such custom applications in the Near-Real-Time (RT) RIC are called xApps, and enable a variety of use cases related to radio resource management. Despite numerous open-source and commercial projects focused on the Near-RT RIC, developing and testing xApps that are interoperable across multiple RAN implementations is a time-consuming and technically challenging process. This is primarily caused by the complexity of the protocol of the E2 interface, which enables communication between the RIC and the RAN while providing a high degree of flexibility, with multiple Service Models (SMs) providing plug-and-play functionalities such as data reporting and RAN control. In this paper, we propose xDevSM, an open-source flexible framework for O-RAN service models, aimed at simplifying xApp development for the O-RAN Software Community (OSC) Near-RT RIC. xDevSM reduces the complexity of the xApp development process, allowing developers to focus on the control logic of their xApps and moving the logic of the E2 service models behind simple Application Programming Interfaces (APIs). We demonstrate the effectiveness of this framework by deploying and testing xApps across various RAN software platforms, including OpenAirInterface and srsRAN. This framework significantly facilitates the development and validation of solutions and algorithms on O-RAN networks, including the testing of data-driven solutions across multiple RAN implementations.

翻译：无线接入网智能控制器（RIC）是O-RAN架构中支持数据驱动闭环控制的可编程平台。它们从无线接入网（RAN）收集遥测数据，在定制化应用程序中进行处理，并对RAN实施控制或新配置。近实时（Near-RT）RIC中的此类定制化应用程序称为xApp，能够实现与无线资源管理相关的多种用例。尽管已有大量专注于近实时RIC的开源和商业项目，但开发并测试可在多种RAN实现方案间互操作的xApp仍是耗时且技术挑战巨大的过程。这主要源于E2接口协议的复杂性——该协议在支持RIC与RAN间通信的同时提供了高度灵活性，其多种服务模型（SM）可提供数据上报和RAN控制等即插即用功能。本文提出xDevSM：一个面向O-RAN服务模型的开源灵活框架，旨在为O-RAN软件社区（OSC）近实时RIC简化xApp开发流程。xDevSM通过将E2服务模型的逻辑封装至简洁的应用程序接口（API）之后，降低了xApp开发复杂度，使开发者能专注于xApp的控制逻辑设计。我们通过在OpenAirInterface和srsRAN等多种RAN软件平台上部署测试xApp，验证了该框架的有效性。该框架显著促进了O-RAN网络解决方案与算法的开发验证，包括跨多RAN实现方案的数据驱动解决方案测试。