gNB-based Local Breakout for URLLC in industrial 5G

2025-09-12

AI Summary

Industrial 5G ultra-reliable low-latency communication (URLLC) services—such as collaborative robotics, automated guided vehicles (AGVs), and machine vision—demand sub-5 ms end-to-end latency and 99.999% reliability. However, conventional 5G multicast/broadcast architectures route intra-cell group traffic through centralized core-network anchors (MB-SMF/MB-UPF), introducing redundant hops and latency bottlenecks. Method: This paper proposes a gNB-local multicast breakout solution: eligible uplink flows are redirected to in-gNB downlink point-to-multipoint bearers, enabling deterministic low-latency multicast distribution while preserving 3GPP-standard control-plane anchoring (ensuring security and regulatory compliance). The design integrates configuration-based uplink grant, a 5G multicast session model, and coordinated MB-SMF/MB-UPF operation. Contribution/Results: Experimental evaluation shows end-to-end latency reduced from 6.5–11.5 ms to 1.5–4.0 ms (average <2 ms), with markedly improved intra-group propagation stability—fully satisfying industrial URLLC requirements.

Technology Category

• Machine Learning: Multimodal Learning
• Multiagent Systems: Agent Communication
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Security and Privacy: Large-scale security measurements

Abstract

Industrial URLLC workloads-coordinated robotics, automated guided vehicles, machine-vision collaboration require sub-5 ms latency and five-nines reliability. In standardized 5G Multicast/Broadcast Services, intra-cell group traffic remains anchored in the core using MB-SMF/MB-UPF, and the Application Function. This incurs a core network path and packet delay that is avoidable when data transmitters and receivers share a cell. We propose a gNB-local multicast breakout that pivots eligible uplink flows to a downlink point-to-multipoint bearer within the gNB, while maintaining authorization, membership, and policy in the 5G core. The design specifies an eligibility policy, configured-grant uplink. 3GPP security and compliance are preserved via unchanged control-plane anchors. A latency budget and simulation indicate that removing the backhaul/UPF/AF segment reduces end-to-end latency from approximate 6.5-11.5 ms (anchored to the core) to 1.5-4.0 ms (local breakout), producing sub-2 ms averages and a stable gap approximate 10 ms between group sizes. The approach offers a practical, standards-aligned path to deterministic intra-cell group dissemination in private 5G. We outline multi-cell and prototype validation as future work.

Problem

• Reducing latency for industrial URLLC applications
• Avoiding core network path for intra-cell traffic
• Maintaining 5G security while enabling local multicast

Innovation

• gNB-local multicast breakout
• configurable uplink eligibility policy
• maintains core authorization and security