Deterministic communications are essential to meet the stringent delay and jitter requirements of Industrial Internet of Things (IIoT) services. IIoT increasingly demands wide-area wireless mobility to support Autonomous Mobile Robots (AMR) and dynamic workflows. Integrating Time-Sensitive Networking (TSN) with 5G private networks is emerging as a promising approach to fulfill these requirements. In this architecture, 5G provides wireless access for industrial devices, which connect to a TSN backbone that interfaces with the enterprise edge/cloud, where IIoT control and computing systems reside. TSN achieves bounded latency and low jitter using IEEE 802.1Qbv Time-Aware Shaper (TAS), which schedules the network traffic in precise time slots. However, the stochastic delay and jitter inherent in 5G disrupt TSN scheduling, requiring careful tuning of TAS parameters to maintain end-to-end determinism. This paper presents an empirical study evaluating the impact of 5G downlink delay and jitter on TAS scheduling using a testbed with TSN switches and a commercial 5G network. Results show that guaranteeing bounded latency and jitter requires careful setting of TAS transmission window offset between TSN switches based on the measured 5G delay bounded by a high order p-th percentile. Otherwise, excessive offset may cause additional delay or even a complete loss of determinism.

翻译：确定性通信对于满足工业物联网（IIoT）服务严格的延迟与抖动要求至关重要。IIoT日益需要广域无线移动性以支持自主移动机器人（AMR）和动态工作流。将时间敏感网络（TSN）与5G专网融合正成为一种满足这些需求的有前景的方案。在此架构中，5G为工业设备提供无线接入，设备连接至与企业边缘/云对接的TSN骨干网，IIoT控制与计算系统即部署于此。TSN通过IEEE 802.1Qbv时间感知整形器（TAS）实现有界延迟与低抖动，该整形器在精确时隙中调度网络流量。然而，5G固有的随机延迟与抖动会干扰TSN调度，需要精细调整TAS参数以维持端到端确定性。本文通过搭建包含TSN交换机和商用5G网络的测试平台，实证评估了5G下行链路延迟与抖动对TAS调度的影响。结果表明，要保证有界延迟与抖动，必须基于以高阶p百分位数界定的实测5G延迟，谨慎设置TSN交换机间的TAS传输窗口偏移量。否则，过大的偏移可能导致额外延迟甚至完全丧失确定性。