An O-RAN-Based Resource-Aware Conditional Handover and Local Breakout Architecture for 5G Private Networks with Non-3GPP Access Integration

Abstract

This paper presents a resource-aware dynamic network selection and Local Breakout (LBO) architecture under the O-RAN framework to fulfill the high-reliability and lowlatency requirements of smart factories. In Industrial 5G Non-Public Networks (NPN), integrating heterogeneous networks (e.g., 5G NR and untrusted Wi-Fi) is essential for accommodating a massive number of diverse industrial devices. However, conventional handover mechanisms primarily rely on Singlemetric Signal Strength (RSSI/RSRP), often leading to network congestion, unnecessary handovers, and service degradation. To address these challenges, we introduce a FlexRIC-based Conditional Handover (CHO) xApp and a KPM xApp that enable real-time tracking of cellular Physical Resource Blocks (PRBs) and N3IWF CPU utilization. Handovers are triggered via multicriteria evaluation rather than signal strength alone, reducing handover failure rates. Furthermore, an Integrated Local Breakout (I-UPF) Module is proposed within the OAI-CU to achieve session continuity and maintain IP address consistency across 3GPP and non-3GPP access points based on IMSI mapping. Experimental verification is conducted using Free5GC and OpenAirInterface (OAI) emulators. The results demonstrate that the proposed architecture successfully achieves seamless vertical handovers and high-efficiency local data steering without modifications to the standard 5G Core Network, ensuring strict QoS/QoE for smart factory automation.