ISAC-Oriented Beamforming Feedback Design and Optimization for WiFi Systems

With the widespread deployment of WiFi devices, utilizing beamforming feedback for sensing has become a popular trend in WiFi systems. However, the singular value decomposition (SVD)-based feedback method adopted in existing WiFi standards performs poorly in sensing performance since it only aims at maximizing the communication performance. To address this, we propose an integrated sensing and communication (ISAC)-oriented beamforming feedback protocol, which provides different sensing information based on the sensing indicator. Accordingly, we develop different ISAC-oriented CSI compression methods for different sensing applications requiring different feedback information. Taking the angle of departure (AoD) as an example, an optimization problem is formulated to maximize the data rate while preserving the complete AoD information. To resolve it, we propose an iterative algorithm to obtain the suboptimal solution and a heuristic algorithm to reduce the computational complexity. We further extend the proposed compression method for the AoD information to the compression of the angle of arrival (AoA) and time of flight (ToF). Test results show that our proposal achieves both excellent communication and sensing performance and can be applied to various sensing applications, such as localization and action recognition.