A New Wireless Communication Device: The Human Body

Already many of us have multiple electronic devices on our person and this will only increase in the coming years as the internet-of-things comes to fruition. Cell phones, smart watches, computerized eyewear, and health and fitness monitors will all need to communicate with one another to realize their full potential. Currently, Bluetooth is the standard means by which this is achieved, but it is highly energy-inefficient. Now scientists have demonstrated a new way for these devices to share information – by sending magnetic signals through the human body itself.

Smart watch: Sony's smart watch is just one example of a device that will benefit from a new low-power means of communication.Smart watch: Sony's smart watch is just one example of a device that will benefit from a new low-power means of communication.

The study was led by UC San Diego Department of Electrical and Computer Engineering professor Patrick Mercier and was designed to surmount a common problem encountered with Bluetooth communication, that of “path loss”. Bluetooth radios use electromagnetic radiation to transmit data, but these radio waves do not pass easily from one side of the human body to the other. This signal obstruction is known as “path loss” and requires additional power to overcome. Magnetic signals, on the other hand, pass easily through human tissues and this fact provided the impetus for the study.

Prototypical magnetic communication coils: graduate student Jiwoong Park demonstrates magnetic field human body communication. Image from UC San Diego.Prototypical magnetic communication coils: graduate student Jiwoong Park demonstrates magnetic field human body communication. Image from UC San Diego.

The technique introduced is known as magnetic field human body communication and scientists this month have now proven for the first time that it is an effective means of data transmission between wearable devices. Their prototype was a simple proof-of-concept system involving copper wires wrapped around the head, arms, and legs of a subject. Low power magnetic communication was then demonstrated between arm and arm, arm and leg, and arm and head. They showed that the path losses associated with magnetic field communication are on the order of 10 million times less than those from Bluetooth radios. Says Mercier, "This technique, to our knowledge, achieves the lowest path losses out of any wireless human body communication system that's been demonstrated so far. This technique will allow us to build much lower power wearable devices."

There are numerous advantages to the lower power consumption inherent in magnetic field techniques. Foremost among them is the longer battery life for wireless devices. The need for constant recharging is a major stumbling block in the roll out of smart watches and the like and keeps many consumers on the fence. A second benefit would be enhanced security as the wireless signals sent magnetically through the body could not be eavesdropped on by nearby devices. PhD student Jiwoong Park who worked on the project makes the point that this could be particularly relevant where health monitoring devices are concerned.

Of course, of the most interest to consumers is the safety of employing their bodies as data transmitters. Are there any health effects to a constant onslaught of magnetic fields through bodily tissue? The researchers say “no”. Because the fields are designed for ultra-low-power consumption, the strength of the magnetic signals will be too low to pose serious health effects – many, many times lower than MRI scans or wireless implants, for example. Despite this, expect to see some pushback from nervous customers. How comfortable would you be having your body act as the information conveyer between your various electronic devices? Is an extra day of battery life on your Apple watch worth it? We’ll find out soon enough as the team has plans to develop this prototype to commercial availability.

Via Science Daily and UC San Diego.