WiFi Sensing with Single-Antenna Devices for Ambient Assisted Living

Abstract

The absolute coverage WiFi networks is higher than it has ever been and WiFi sensing offers a device-free, contactless alternative to intrusive wearable devices for a variety of applications, in particular for ambient assisted living (AAL). However, a majority of sensing systems proposed in literature use multiple antennas for sensing, resulting in high cost that hinders development of such solutions in real life. This work surveys existing single-antenna systems as a low-cost solution in an AAL scenario. The capabilities of these systems are examined regarding their practical applicability based on testing in AAL environments, leveraging multiple links (i.e. transmitter-receiver pairs) and considering mobile and repositioned receivers. It is found that while the AAL use-cases of respiration monitoring, fall detection and activity recognition are realised by existing systems, further testing in realistic AAL environments with the inclusion of activities of daily living is needed. Additionally the full use of multiple links and consideration of a mobile receiver is still rare, but shows promising improvements. A multi-task system enabling all three applications is discussed using the Model for Ethical Evaluation of Socio-Technical Arrangements (MEESTAR). We suggest an ethically sensitive use, but identify a need for mitigation strategies to address privacy-related concerns of potentially unwilling users.