In-Band Context Signaling for Cross-Layer QoS in Software-Defined Local 5G

In this paper, we propose a flexible cross-layer QoS control scheme for software-defined Local 5G networks. Our approach embeds application and wireless context into the 5G bearer using in-band PDCP-layer signaling. By inserting custom PDCP trailers, our method enables the base station to apply fine-grained QoS policies tailored to real-time application requirements and radio conditions. We prototype this approach using open-source 5G software (OAI/Free5GC) and demonstrate negligible latency overhead (~0.1 ms) on an SDR-based testbed. We further introduce a novel "spatiotemporal slicing" concept, dynamically controlling bandwidth based on UWB-derived location data. Our cross-layer design offers a practical, reproducible foundation for context-aware 6G research.