Ultrasonic vs. Magnetic Resonance Communication for Mixed Wearable and Implanted Devices

Human body communication (HBC) has recently been explored extensively both for small wearable electronic gadgets and for implanted sensors to deliver relevant data to implanted therapeutic devices. In this paper, we conduct an experimental comparison of two of the promising technologies but for on-body use, namely ultrasound coupling (USC) and magnetic resonance coupling (MRC) based communications. We find that both of these propagate much better through the body than in the air, thereby making them attractive for communications between in-body nodes, in-body to on-body nodes, and on-body nodes where the direct path includes substantial body area. USC also involves a surface acoustic wave (SAW) between on-body nodes which may be broken to varying extent by clothing. We find that with SAW component, USC works better than MRC, but otherwise has similar performance. MRC is very robust and can travel up to the entire body length with 25dB or less loss.