The network data analytics function (NWDAF) has been introduced in the fifth-generation (5G) core standards to enable event-driven analytics and support intelligent network automation. However, existing implementations remain largely proprietary, and open-source alternatives lack comprehensive support for end-to-end event subscription and notification. In this paper, we present an open source NWDAF framework integrated into an existing Free5GC implementation, which serves as an open-source 5G core implementation. Our implementation extends the session management function to support standardized event exposure interfaces and introduces custom-built notification mechanisms into the SMF and the access and mobility management function for seamless data delivery. The NWDAF subscribes to events and generates analytics on user equipment (UE) behavior, session lifecycle, and handover dynamics. We validate our system through a two-week deployment involving four virtual next-generation NodeBs (gNBs) and multiple virtual UEs with dynamic mobility patterns. To demonstrate predictive capabilities, we incorporate a mobility-aware module that achieves 80.65\% accuracy in forecasting the next gNB handover cell. The framework supports reliable UE registration, state tracking, and cross-cell handovers.

翻译：网络数据分析功能（NWDAF）已被引入第五代（5G）核心标准，以实现事件驱动分析并支持智能网络自动化。然而，现有实现方案大多仍为专有系统，开源替代方案则缺乏对端到端事件订阅与通知的全面支持。本文提出一种集成于现有Free5GC实现（作为开源5G核心实现）的开源NWDAF框架。该实现扩展了会话管理功能以支持标准化事件暴露接口，并在SMF及接入与移动性管理功能中引入定制化通知机制，以实现无缝数据传递。NWDAF通过订阅事件，对用户设备（UE）行为、会话生命周期及切换动态生成分析结果。我们通过为期两周的部署验证了系统性能，该部署包含四个虚拟下一代基站（gNB）及多个具有动态移动模式的虚拟UE。为展示预测能力，我们集成了一种移动感知模块，其在预测下一gNB切换小区时达到80.65%的准确率。该框架支持可靠的UE注册、状态跟踪及跨小区切换功能。