Assisting Living by Wireless Sensing: The Role of Integrated Sensing and Communications in 6G Era

Advance in wireless communication and signal processing facilitates integrated sensing and communication (ISAC) -- a technology that combines sensing and communication functionalities to efficiently utilize congested wireless/hardware resources, and to pursue mutual benefits. Consequently, the future communications network will be perceptive. In this article, we provide a review of human-related sensing in the context of ISAC. We first present a general ISAC receiver signal processing framework, with a focus on human activity recognition (HAR). Based on geographical deployments, we then categorize current ISAC HAR into three classical configurations, namely monostatic, bi-static and distributed deployments, and discuss their properties, critical research problems and solutions. In order to facilitate system realization and improve the recognition performance, we further explore inherent connections between physical-layer system parameters and HAR performance metrics. Finally, we review major technical challenges and identify key open research problems.