# Time-Sensitive Networking in IEEE 802.11 be: On the Way to Low-Latency WiFi 7
## 1 Introduction  
The number and type of devices that use Internet to communicate is rapidly increasing, and they are also gaining both complexity and heterogeneity. Within this context, we can find from simple sensor/actuator devices with limited capabilities to high quality video cameras and displays, as well as a myriad of novel wearables ranging from health monitoring devices to Virtual Reality glasses. All of them define what we know as the Internet of Things (IoT) [1]. In recent years, a growing number of heterogeneous productive and entertainment sectors is promoting the development of the IoT towards the support of delay-sensitive applications. This evolution is motivated by the latest technological advances in multimedia, cloud computing, artificial intelligence, automation, robotics, and unmanned vehicles, among many other aspects. They all are fostering the emergence of cutting-edge real-time applications which strongly depend on extremely low latency and, occasionally, very high bandwidth-demanding communications for their successful operation. Since its emergence in the early 2000s, WiFi's worldwide success has been mainly substantiated by its high flexibility, mobility of devices, better cost efficiency, and reduced complexity than other solutions. Although WiFi has been constantly evolving through successive amendments to improve peak throughput, capacity, and efficiency, it has not yet been able to produce an effective solution to manage time-sensitive traffic with bounded low latency. To address the requirements of emerging real-time applications within IEEE 802.11-based networks, initiatives like the Real-Time Application Technical Interest Group (RTA TIG) [2] are promoting physical (PHY) and medium access control (MAC) enhancements, as well as new capabilities under the time-sensitive networking (TSN) framework. Originally intended for Ethernet, TSN sub-standards, which ensure zero packet loss due to buffer congestion, extremely low packet loss due to equipment failure, and guaranteed upper bounds on end-to-end latency [3], are now making their way to wireless networks. The IEEE P802.11 be Task Group (TGbe) [4] was created in May 2019 to address the design of a new PHY and MAC amendment. Considered as the successor of IEEE 802.11 ax [5] and the core piece of next WiFi 7, IEEE 802.11 be aspires to achieve a peak throughput of 30 Gbps and incorporate disruptive solutions in the WiFi ecosystem such as multi-link operation and multi-access point (multi-AP) coordination [6]. At the same time, IEEE 802.11 be also targets reducing worst-case latency and jitter in wireless local area networks (WLANs), for which TSN sub-standards are currently under study for their possible adoption or integration. Indeed, to be used as part of a potential IEEE 802.11 be low-latency operation mode, original TSN mechanisms will need to be redesigned taking into consideration the inherent constraints of the wireless medium (namely, unreliability of links, asymmetric path delay, channel interference, signal distortion, lack of accurate clock synchronization methods, and incompatibility of network interface cards) [7], while ensuring backward compatibility with legacy WiFi devices. Overall, wireless TSN opens new research directions for the upcoming years, and not only in the WiFi ecosystem [8]. In fact, the 3 GPP mobile standards body has also defined ultra-reliable low-latency communications (URLLC) as one of the main application areas for the enhanced capabilities of 5G. Latency reduction techniques and support to deterministic communications have long been in the spotlight of low-power wireless sensor networks, particularly as a result of the specialized MAC-layer profiles introduced in IEEE 802.15.4e. This paper introduces the future IEEE 802.11 be amendment, discussing how its new features can be used to support a seamless adoption of TSN mechanisms.