Human-motion based transmission power control in wireless body area networks

The development of a transmission power control (TPC) protocol for wireless body area networks (WBANs) is proposed. The WBAN consists of wireless sensors attached to the user. Each sensor has a transceiver and an inertial measurement unit (IMU) to measure user's motion. The TPC protocol increases the WBAN's lifetime by reducing the power consumption of the transceiver. The protocol is based on a mathematical model of the human motion performed by the user. It uses the model to determine the minimum transmission power required to achieve a packet delivery ratio (PDR). The TPC protocol uses the received signal strength indicator (RSSI) to characterize the channel. It uses IMU measurements to determine the parameters of the model and then decide on transmission-power levels. Also, the TPC protocol includes a method to reduce the complexity of the human-motion model to reduce the calculations the wireless sensor has to perform. The TPC protocol is implemented and tested real-time on a Shimmer2r wireless sensor. Experimental results on a bicep-curl movement show that the average power per packet decreased from 31.3mW to 19.0mW, which is a reduction of 39%, while maintaining the PDR within a 4% difference from the target PDR.