Design and Performance Evaluation of an Implantable Ultrasonic Networking Platform for the Internet of Medical Things

Wireless networks of electronically controlled implantable medical sensors and actuators will be the basis of many innovative and potentially revolutionary therapies. The biggest obstacle in realizing this vision of networked implants is posed by the dielectric nature of the human body, which strongly attenuates radio-frequency (RF) electromagnetic waves. In this paper we present the first hardware and software architecture of an Internet of Medical Things (IoMT) platform with ultrasonic connectivity for intra-body communications. This platform can be used as a basis for building future IoT-ready medical implants and wearable devices. We demonstrate that ultrasonic waves can be efficiently generated and received with low-power mm-sized components, and that despite the conversion loss introduced by ultrasonic transducers, the attenuation of 2.4 GHz RF is substantially greater than ultrasound, e.g., ultrasound attenuates 70 dB less than RF at distances over 10 cm. We show that the proposed IoMT platform requires significantly less transmission power than 2.4 GHz RF with equal reliability, e.g., 35 dBm less at distances over 12 cm with 10(-3) Bit Error Rate (BER) thus enabling a lower energy per bit and a longer device lifetime. Finally, we experimentally establish 2.4 GHz RF links do not function at distances greater than 12 cm, while ultrasonic links achieve a reliability of 10(-6) BER up to a distance of 20 cm with less than 0 dBm transmission power.