SDAP-based QoS Flow Multiplexing Support in Simu5G for 5G NR Simulation

The Service Data Adaptation Protocol (SDAP) plays a central role in 5G New Radio (NR), acting as a bridge between the core and radio networks, by enabling QoS Flow multiplexing over shared Data Radio Bearers (DRBs). However, most 5G simulation frameworks, including the popular OMNet++-based Simu5G, lack SDAP support, limiting their ability to model realistic QoS behavior. This paper presents a modular, standardscompliant SDAP extension for Simu5G. The implementation includes core elements such as QoS Flow Identifer (QFI) flow tagging, SDAP header insertion/removal, and configurable logical DRB mapping. The proposed design supports multi-QFI simulation scenarios and enables researchers to model differentiated QoS flows and flowaware scheduling policies. Validation results confirm correct SDAP behavior and pave the way for advanced 5G simulations involving per-flow isolation, latency-sensitive traffic, and industrial QoS profiles.