Industrial 5G deployments using Time Division Duplex (TDD) networks face a critical challenge: existing schedulers rely on static configuration of Uplink (UL) to Downlink (DL) resource ratios, failing to adapt to dynamic asymmetric traffic demands. This limitation is particularly problematic in Industry 4.0 scenarios where traffic patterns exhibit significant asymmetry between directions and heterogeneous Quality of Service (QoS) requirements. We present FLEX, a novel QoS-aware scheduler that dynamically adjusts the UL/DL ratio in flexible TDD slots while respecting diverse QoS requirements. FLEX introduces DL buffer state estimation to prevent starvation of high-priority DL traffic, exploiting the deterministic nature of industrial traffic patterns for accurate predictions. Through extensive simulations of industrial scenarios using 5G LENA and ns-3, we demonstrate that FLEX achieves similar throughput compared to established scheduling while correctly enforcing QoS priorities in both traffic directions. For deterministic traffic patterns, FLEX maintains minimal latency overhead (less than 1 slot duration), making it particularly suitable for industrial automation applications.

翻译：采用时分双工（TDD）网络的工业5G部署面临一项关键挑战：现有调度器依赖静态配置的上行（UL）与下行（DL）资源比例，无法适应动态非对称流量需求。这一局限在工业4.0场景中尤为突出——其流量模式在方向间呈现显著非对称性且存在异构服务质量（QoS）需求。我们提出FLEX，一种新型QoS感知调度器，可在灵活TDD时隙中动态调整UL/DL比例，同时满足多样化QoS要求。FLEX引入下行缓冲区状态估计机制，通过利用工业流量模式的确定性特征进行精确预测，防止高优先级下行流量出现饿死现象。基于5G LENA与ns-3对工业场景的广泛仿真表明：FLEX在维持与传统调度方案相近吞吐量的同时，能够正确执行两个流量方向的QoS优先级。针对确定性流量模式，FLEX保持极低的延迟开销（小于1个时隙长度），使其特别适用于工业自动化应用。