*Article* **Wi-Fi-Based Location-Independent Human Activity Recognition via Meta Learning**

**Xue Ding 1, Ting Jiang 1, Yi Zhong 2,\*, Yan Huang <sup>3</sup> and Zhiwei Li <sup>1</sup>**


University of Technology Sydney, Sydney, NSW 2007, Australia; Yan.Huang-3@student.uts.edu.au **\*** Correspondence: yi.zhong@bit.edu.cn

**Abstract:** Wi-Fi-based device-free human activity recognition has recently become a vital underpinning for various emerging applications, ranging from the Internet of Things (IoT) to Human– Computer Interaction (HCI). Although this technology has been successfully demonstrated for location-dependent sensing, it relies on sufficient data samples for large-scale sensing, which is enormously labor-intensive and time-consuming. However, in real-world applications, locationindependent sensing is crucial and indispensable. Therefore, how to alleviate adverse effects on recognition accuracy caused by location variations with the limited dataset is still an open question. To address this concern, we present a location-independent human activity recognition system based on Wi-Fi named WiLiMetaSensing. Specifically, we first leverage a Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) feature representation method to focus on locationindependent characteristics. Then, in order to well transfer the model across different positions with limited data samples, a metric learning-based activity recognition method is proposed. Consequently, not only the generalization ability but also the transferable capability of the model would be significantly promoted. To fully validate the feasibility of the presented approach, extensive experiments have been conducted in an office with 24 testing locations. The evaluation results demonstrate that our method can achieve more than 90% in location-independent human activity recognition accuracy. More importantly, it can adapt well to the data samples with a small number of subcarriers and a low sampling rate.

**Keywords:** Wi-Fi sensing; human activity recognition; location-independent; meta learning; metric learning; few-shot learning
