Effects of Antenna Orientation in Fall Detection Systems Based on WiFi Signals

The global increase in human life expectancy has created a need for healthcare and remote monitoring technology suitable for the elderly. One of the biggest health treats to older adults are falls occurring at home during daily activities. This reality has prompted the design of device-free fall detection systems that employ WiFi signals as sensing probes. Several works have addressed the design and development of these detection platforms. However, these works have not considered the impact of the antenna orientation on the system's sensing capabilities. To close the gap, we present a systematic analysis of the effects of antenna orientation on the performance of a WiFi-based fall detection systems. The analysis was conducted on the grounds of an experimental platform that transmits WiFi-like waveforms from which the Doppler signature of a fall event can be computed. Our work shows how the orientation of the antenna affects spectrograms of the received probe signal. The results also show that signals transmitted with a horizontal positioning improve the performance in the classification stage.