Open Radio Access Networks (O-RAN) enable the disaggregation of radio access functions and the deployment of control applications across different timescales. However, designing interoperable control schemes that jointly exploit long-term traffic awareness and near-real-time radio resource optimization remains a challenging problem, particularly under dense multi-cell interference and heterogeneous service demands. This paper proposes an interoperable rApp/xApp-driven dynamic spectrum allocation (DSA) framework for O-RAN, based on a graph-theoretic formulation of physical resource block (PRB) assignment. The proposed architecture leverages a non-real-time radio intelligent controller (Non-RT RIC) rApp to predict aggregated traffic evolution and generate high-level spectrum policies at the minutes timescale, while a near-real-time RIC (Near-RT RIC) xApp constructs a user-centric conflict graph and performs fairness-aware PRB allocation at sub-second timescales. To mitigate persistent user starvation, a conflict-aware modified proportional fair (MPF) scheduling mechanism is applied, enabling controlled interference-free PRB time-sharing. Extensive simulation results demonstrate that the proposed framework significantly improves the PRB assignment success rate (above 90%) and service-share fairness (above 85%) across different channel configurations and user demands, while maintaining architectural separation and rApp/xApp interoperability in accordance with O-RAN principles.

翻译：开放无线接入网络（O-RAN）支持无线接入功能的解耦以及控制应用在不同时间尺度上的部署。然而，设计能够联合利用长期流量感知与近实时无线资源优化的互操作控制方案，尤其是在密集多小区干扰和异构业务需求下，仍然是一个具有挑战性的问题。本文提出一种基于图论的物理资源块（PRB）分配模型，构建了一个面向O-RAN的互操作rApp/xApp驱动动态频谱分配（DSA）框架。该架构利用非实时无线智能控制器（Non-RT RIC）中的rApp预测聚合流量演变，并在分钟级时间尺度生成高层频谱策略；同时，近实时无线智能控制器（Near-RT RIC）中的xApp构建以用户为中心的冲突图，并在亚秒级时间尺度执行考虑公平性的PRB分配。为缓解持续的用户资源匮乏问题，采用了一种冲突感知的改进比例公平（MPF）调度机制，实现受控的无干扰PRB分时复用。大量仿真结果表明，所提框架在不同信道配置和用户需求下，显著提升了PRB分配成功率（高于90%）与业务份额公平性（高于85%），同时遵循O-RAN原则保持了架构分离与rApp/xApp的互操作性。