Monitoring of Limb Movement Activities during Physical Exercises using UWB Channel Parameters

Abstract

This paper investigates ultra-wideband channel (4–8 GHz) characteristics during various upper limb movement activities for health monitoring applications. Two on-body channel parameters are analyzed which are path loss magnitude (PL) and rms delay spread $(\boldsymbol{\sigma}_{\boldsymbol{\tau}})$. The compact wearable antennas are placed on the wrist in two different locations (outer and inner wrist). Five limb movement activities are performed by real human subject in an indoor environment related to forward, backward, sideways motion and arm bending. It is observed that different position of the arms lead to different channels links for each activity considered. The LOS/NLOS channels generally have a PL magnitude of 45-55/60-65 dB and $\boldsymbol{\sigma}_{\boldsymbol{\tau}}$ of 0.5-5/6-35 nsec respectively. Arm bending activity results in minimum PL (48/60 dB) and $\boldsymbol{\sigma}_{\boldsymbol{\tau}}$ (0.5-2/6-15 nsec) for LOS/NLOS links as the distance between the two antennas (placed on the wrist and shoulder) is least.