With recent advancements, the wireless local area network (WLAN) or wireless fidelity (Wi-Fi) technology has been successfully utilized to realize sensing functionalities such as detection, localization, and recognition. However, the WLANs standards are developed mainly for the purpose of communication, and thus may not be able to meet the stringent requirements for emerging sensing applications. To resolve this issue, a new Task Group (TG), namely IEEE 802.11bf, has been established by the IEEE 802.11 working group, with the objective of creating a new amendment to the WLAN standard to meet advanced sensing requirements while minimizing the effect on communications. This paper provides a comprehensive overview on the up-to-date efforts in the IEEE 802.11bf TG. First, we introduce the definition of the 802.11bf amendment and its formation and standardization timeline. Next, we discuss the WLAN sensing use cases with the corresponding key performance indicator (KPI) requirements. After reviewing previous WLAN sensing research based on communication-oriented WLAN standards, we identify their limitations and underscore the practical need for the new sensing-oriented amendment in 802.11bf. Furthermore, we discuss the WLAN sensing framework and procedure used for measurement acquisition, by considering both sensing at sub-7GHz and directional multi-gigabit (DMG) sensing at 60 GHz, respectively, and address their shared features, similarities, and differences. In addition, we present various candidate technical features for IEEE 802.11bf, including waveform/sequence design, feedback types, as well as quantization and compression techniques. We also describe the methodologies and the channel modeling used by the IEEE 802.11bf TG for evaluation. Finally, we discuss the challenges and future research directions to motivate more research endeavors towards this field in details.

翻译：随着最新进展，无线局域网（WLAN）或无线保真（Wi-Fi）技术已成功用于实现检测、定位和识别等感知功能。然而，WLAN标准主要面向通信目的开发，因此可能无法满足新兴感知应用的严苛需求。为解决此问题，IEEE 802.11工作组设立了新的任务组（TG），即IEEE 802.11bf，其目标是为WLAN标准制定新修订版，以满足高级感知需求的同时将对通信的影响降至最低。本文全面概述了IEEE 802.11bf TG的最新工作进展。首先，我们介绍了802.11bf修订版的定义、组建过程及标准化时间表。接着，我们讨论了WLAN感知用例及其对应的关键性能指标（KPI）需求。在回顾基于通信导向WLAN标准的早期WLAN感知研究后，我们指出了其局限性，并强调了实际中需要802.11bf中这一新型感知导向修订版的必要性。此外，我们分别探讨了用于测量采集的WLAN感知框架与流程，涵盖sub-7GHz感知和60 GHz定向多吉比特（DMG）感知，并分析了其共享特征、相似性与差异。同时，我们介绍了IEEE 802.11bf的多种候选技术特性，包括波形/序列设计、反馈类型以及量化与压缩技术。我们还描述了IEEE 802.11bf TG用于评估的方法论与信道建模。最后，我们详细讨论了挑战与未来研究方向，以激励该领域更多研究工作。