Interoperable rApp/xApp Control over O-RAN for Mobility-aware Dynamic Spectrum Allocation

TL;DR

This paper introduces an interoperable control framework for O-RAN that combines long-term traffic prediction with real-time spectrum management, significantly enhancing resource allocation fairness and success rates in dense multi-cell environments.

Contribution

It presents a novel graph-theoretic, multi-timescale spectrum allocation framework utilizing rApps and xApps, improving interoperability and resource efficiency in O-RAN networks.

Findings

PRB assignment success rate exceeds 90%

Service-share fairness exceeds 85%

Framework effectively manages dense multi-cell interference

Abstract

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.