Enabling QoS Provisioning Support for Delay-Critical Traffic and Multi-Flow Handling in ns-3 5G-LENA

Technology evolution in mobile communication networks has brought a revolution in the everyday life allowing new and innovative applications to be established in the fields of healthcare, education, industry, and gaming, among others. Most of these applications, however, require very low latencies and are characterized as delay-critical. Moreover, immersive applications, such as eXtended Reality (XR), generate multi-flow traffic with varying Quality-of-Service (QoS) characteristics. Proper QoS handling, therefore, becomes crucial. 5G New Radio (NR) is considered to be an enabler for such applications thanks to its capabilities, including the introduction of a new QoS framework that moves QoS control at the level of a flow. In this work, we focus on the 5G QoS model and we present and implement in the nr module of the ns-3 simulator, a novel QoS MAC scheduler that performs QoS provisioning at the flow level, and is able therefore to handle multi-flow traffic, by considering QoS characteristics of each flow (e.g., resource type), along with real-time MAC measurements. For this we additionally extend the nr module with a new design for QoS assignment at the level of Logical Channels at the MAC layer and we introduce support for delay-critical Guaranteed Bit Rate (GBR) flows. We evaluate the proposed implementation through system-level simulations using a newly implemented scenario with multi-flow traffic and we compare the performance to that of traditional schedulers. Results demonstrate that the proposed solution is able to prioritize delay-critical traffic, reduce significantly its delay and guarantee its QoS requirements.