Design Options for Aggregators for In-Body Networks

The prevalence of medical implants grows significantly and with it comes a need to network these devices inside the human body. Such an in-body wireless network needs a gateway that provides a connection between the in-body network and the external world. We call this gateway the aggregator. Focusing on radio frequency (RF) communication through fat tissue as our intra-body communication paradigm, we explore multiple design options for the aggregator with engineering, security, and medical considerations in mind. We discuss a partially implanted on-skin design and a non-invasive on-skin design for the aggregator. The partially implanted design avoids the losses that human skin present to microwave signals, but requires the patient to go through an invasive procedure. The on-skin aggregator design is easier to realize, but the communication range inside the body is shorter. An implanted wirelessly powered repeater node enables longer communication distances inside the body but requires surgery for the implant. Our discussions show that there is no design that is best in all scenarios and that the aggregator type should be selected for the application at hand. This work also covers signal leakage mitigation and jamming, which are two strategies that the aggregator can implement in order to preserve the privacy of the in-body communication channel.