Ultra wideband wireless tags for off-body radio channel characterisation with varying subject postures

In this paper the impact of varying human subject postures on the ultra wideband (UWB) off-body radio channels is experimentally investigated. Measurements were made using commercial UWB wearable wireless tags and reader. Statistical path loss parameters of nine off-body channels for seven different body postures are studies and analysed and the effects of the body postures on the path loss variation are investigated. Results show that maximum of 19.19 dB path loss variation of a channel is noticed for different body postures of the subject at the same location. In addition, the path loss was modelled as a function of distance to investigate the changes in the received power with respect to different body postures.