Magnetic Induction Communication in Challenging Environments

Abstract

Radio frequency (RF) communication, although most popular, is unsuitable for environments involving aqueous and animal/plant tissue media, cluttered environments (e.g., small regions with many radios), applications requiring extremely low power consumption, etc. For such environments, magnetic induction (MI) communication appears to be a viable new technology. It has many desirable properties for propagation in challenging environments. In this thesis, we have experimentally explored the use of Magnetic Induction (MI) based communications for communication through the body. Such communication modalities are essential for wireless communication between implanted therapeutic devices. RF is known to work poorly in this environment due to primarily an ionized aqueous propagation media. We have built a custom experimental testbed using magnetic coils and performed simulations of intrabody propagation for MI based communication using the Sim4Life package. Ultrasound (US) communications have been explored extensively for intra-body environments, and we compare MI against US as well. We experimentally showed that ultrasonic coupling (USC) works better than magnetic resonance coupling (MRC) for transmission through the body at 8 MHz frequency, as USC generates more power than MRC. We have also experimentally compared MR coupling against other forms of intra-body communication, such as galvanic and capacitive. We have done a deep in-depth study of in/on body simulation. According to those studies, the simulations work quite well, and yield a percentage error in the power received for USC as 3-4 %, while for MRC, as 4-5 %. The orientation of USC and MRC sensors causes only 1-2 % error, which doesn't have much impact.