# Time-Sensitive Networking in IEEE 802.11 be: On the Way to Low-Latency WiFi 7
## 6 Case Study: Interactive Museum  
Worldwide museums have long relied on IoT-related technologies to display information, give context, and involve visitors in their exhibitions. Well-known examples are informational videos, audio guides, interactive games, hands-on experiments, and smartphone apps. In this regard, the latest advancements on augmented reality (AR) allow its adoption by interactive museums, thus giving curators a chance to layer more information on top of existing exhibits [60]. To cope with the volume, distribution, and dynamic behavior of visitors across the different halls (usually moving far and wide and even creating densely populated clusters of people), the museum's wireless network does not only require the deployment of a high number of APs, but also a coordinated operation under a multi-AP scheme. In the following lines, the case study of an interactive museum is used to illustrate the benefits of integrating a TSN feature such as frame preemption into IEEE 802.11 be. MATLAB is used to simulate the considered scenario on the basis of parameters from Table 3.  
Let us consider a circular hall of radius \(R=15\) m containing an interactive exhibit with a single AP placed in the center, as shown in Figure 7. (Image based on the Google SketchUp model of the Museum Mysteries exhibit of the Waterloo Region Museum located in Kitchener, Canada ([https://3 dwarehouse.sketchup.com/model/ufac3 aabd-f3c2-4 caa-b775-785217b2e9e8/Museum-Mysteries-Exhibit](https://3 dwarehouse.sketchup.com/model/ufac3 aabd-f3c2-4 caa-b775-785217b2e9e8/Museum-Mysteries-Exhibit), accessed on 20 July 2021)). Users are placed uniformly at random on the museum's hall. The AP provides visitors in that hall with a set of customized interactive services by means of DL unicast transmissions that can be categorized according to their priority level:* Best effort (BE) traffic is tagged as low-priority and consists of video streaming of additional contents, an interactive audio guide, and real-time information feeding the museum mobile app. BE traffic amounts to \(B_{\text{BE}}=2\) Mbps per user. * Time-sensitive (TS) traffic is tagged as high-priority and transports a stream of information corresponding to an immersive AR installation. TS traffic amounts to \(B_{\text{TS}}=5\) Mbps per user and has a maximum tolerable latency of \(t_{\text{TS}}=5\) ms. The AP implements two access categories (BE and TS), and supports three different prioritization policies:  
* No prioritization: Packets are sent in strict order of arrival regardless their type (BE or TS). Are all the italisc necessary? If not, please reive. * Non-preemptive prioritization: As long as the TS queue contains packets, they are sent prior to BE ones. In case there is an ongoing transmission of a BE packet, and a new TS packet arrives to the TS queue, the transmission of the latter is delayed until the end of the former one. * Preemptive prioritization: As in the previous policy, TS packets are sent prior to BE ones. However, the transmission of a BE packet is interrupted if a new TS packet arrives. Transmission from the BE packet is resumed only when the transmission of the TS packet finishes and the TS queue is empty. Preemption, however, entails an extra delay caused by overheads of the \(N_{f}\) fragments in which the BE packet is divided (\(N_{f}\cdot T_{ov}\)). Visitors may request low-priority or high-priority services, or even both at the same time. Four different network configurations were considered, being \(N_{\text{BE}}=\{15,20,25,30\}\) users requesting BE services and \(N_{\text{TS}}=5\) users requesting TS services. For each configuration, \(k=1000\) simulations changing user locations were executed.