A Theoretical Analysis of Path Loss Based Activity Recognition

Body area networks are used extensively in the medical field and elderly care. These networks perform a collection of roles including monitoring an individual's activities, through a process known as activity recognition. Current approaches to activity recognition require specialized hardware for advanced sensors which puts stress on battery life. We show that it is theoretically possible to distinguish between different human activities/postures by using radio signal propagation only and provide strategies for doing this. This is immensely beneficial to the field of sensor networks for two reasons: 1) It removes the need for more energy intensive components thus reducing strain on limited power resources and thus 2) reduces form factor for sensor network nodes. We show that activity recognition can be done using only radio signals at low transmit power levels with good accuracy. Lower power consumption and reduced form factor are desirable features for body networks and have been identified as being essential for wide adoption of body networks.