Dynamic on-body channel and its ARQ error control

On-body communication channels are of increasing interest as more and more wireless devices are wearable in medical, military and personal communication applications. Based on our previous study, this paper investigates reasons for time-varying fading of on-body channel and its ARQ error control. We used commercial software POSER7 to generate distance and direction mismatch between on-body antennas during actions and analyzed dynamic path loss based on a measured on-body antenna radiation pattern. The middle and long term fading are attributed to intended movements which can be controlled, and the dominant short term fading is attributed to the mismatch of antenna direction resulting from unintentional movements which cannot be controlled. Backoff strategy for ARQ retransmission to over the dynamic on-body fading is then analyzed on considering QoS criteria and power consumption criteria.