Suitability of NFC for Medical Device Communication and Power Delivery

Near Field Communications (NFC) is a 13.56 MHz inductively coupled power delivery and communication protocol that extends the ISO 14443 RFID standard. Low cost NFC scanner subsystems are anticipated to be widely incorporated in coming generations of commodity cellular phones. We consider the potential of this emerging infrastructure to provide convenient and low cost power distribution and communication channels for a range of medical devices. For example, an NFC device within a cell phone could relay measurements collected from a defibrillator-pacemaker to a monitoring physician, remotely control an insulin pump, or activate an implanted neural simulation system. NFC devices pose similar bio-compatibility challenges to other implanted electronics without requiring the provisioning of battery power to support communication. Furthermore, an NFC communication subsystem´s power-independence provides a measure of defense against potential denial-of-service attacks that consume power in order to discharge a capacity-limited power source. The 13.56 MHz band has minimal interaction with human and animal tissues. We conducted several successful proof-of- concept experiments communicating with with ISO 14443 tags implanted at multiple locations within a human cadaver. Magnetic field strength decays with the cube of distance-to- antenna, limiting limits the range of potential eavesdroppers. At present, NFC protocols do not provide an appropriate set of privacy properties for implanted medical applications. However, NFC devices are implemented using embedded general purpose processors and thus only software modifications would be required to support protocol extensions with enhanced privacy.