3GPP Release~16 specifies how a 5G system can operate as a transparent IEEE~802.1 TSN bridge, yet no existing simulation framework implements the complete bridge architecture with end-to-end QoS mapping through the SDAP layer, per-flow Data Radio Bearer selection, and IEEE~802.1AS transparent clock behaviour with measured residence time. Existing tools model either QoS mapping without time synchronisation, or time synchronisation without a data plane. This paper presents nascTime, a simulation framework built on OMNeT++~6.3, INET~4.6, and Simu5G that implements the full 3GPP 5G-TSN bridge model. The NW-TT and DS-TT are realised as modular compound modules that integrate with INET's \texttt{LayeredEthernetInterface} and streaming PHY. QoS mapping traverses the complete PCP\,$\rightarrow$\,DSCP\,$\rightarrow$\,QFI\,$\rightarrow$\,SDAP/DRB pipeline, and gPTP frames are transported through the simulated 5G radio path via L2-in-GTP-U encapsulation with per-message residence-time correction. We validate the framework with a three-endpoint factory topology under both ideal and fading channel conditions. In the ideal scenario, high-priority traffic achieves 99.9\% delivery with a mean end-to-end delay of 2.58\,ms, while the measured 5GS residence time exhibits a variance below 0.2\,$μ$s. Under a fading channel, residence-time variance increases to 48\,$μ$s, confirming that the framework captures radio-induced timing effects absent from abstract-delay simulators. nascTime is publicly available and constitutes the first full-stack 5G-TSN bridge simulation with SDAP-based QoS differentiation and measured IEEE~802.1AS transparent clock behaviour.

翻译：3GPP Release~16规定了5G系统如何作为透明IEEE~802.1 TSN网桥运行，但现有仿真框架尚未实现完整的网桥架构，包括通过SDAP层的端到端QoS映射、基于逐流的数据无线承载选择，以及含实测驻留时间的IEEE~802.1AS透明时钟行为。现有工具要么建模QoS映射而不考虑时间同步，要么模拟时间同步但缺乏数据平面。本文提出nascTime，一种基于OMNeT++~6.3、INET~4.6和Simu5G构建的仿真框架，实现了完整的3GPP 5G-TSN网桥模型。NW-TT和DS-TT以模块化复合模块形式实现，并与INET的\texttt{LayeredEthernetInterface}和流式PHY集成。QoS映射贯穿完整的PCP\,$\rightarrow$\,DSCP\,$\rightarrow$\,QFI\,$\rightarrow$\,SDAP/DRB流水线，gPTP帧通过L2-in-GTP-U封装经模拟5G无线路径传输，并逐消息进行驻留时间校正。我们采用三端点工厂拓扑，在理想信道与衰落信道条件下验证了该框架。在理想场景下，高优先级流量达到99.9%的交付率，平均端到端时延为2.58\,ms，而实测的5GS驻留时间方差低于0.2\,$μ$s。在衰落信道下，驻留时间方差增至48\,$μ$s，证实该框架能够捕捉抽象时延仿真器无法呈现的无线诱导时序效应。nascTime已公开提供，是首个具备SDAP-based QoS区分能力与实测IEEE~802.1AS透明时钟行为的全栈5G-TSN网桥仿真框架。