PAN: PERSONAL AREA NETWORK.

Anand Gopalan. (TE - Elecs - Fr CRCE)

The field of electronic communication has come a long way from the days of bulky radio trans-receivers. Today a large fraction of this field is focussed on making communication more 'personal', more individual-oriented. The aim being that the user can communicate effectively with any other individual or for that matter with any component of his environment. As a result with electronic devices becoming smaller, lower in power requirements, and less expensive, we have begun to adorn our bodies with personal information and communication appliances. Such devices include cellular phones, personal digital assistants (PDAs), pocket video games, and pagers. The next step is obviously to enable these devices to communicate with each other and also with the individual, effectively forming a network around the user. This is the concept of a Personal Area Network (PAN). If all this sounds like some far of dream in the mind of a frizzy haired scientist it isn't. Scientists at IBM are perfecting a new Personal Area Network technology that uses the natural electrical conductivity of the human body to transmit electronic data.

However the idea of sending an electrical current through you body may not sound very appealing at first. But to IBM researcher’s it is and could bring a whole new meaning to putting information at one’s fingertips. At the moment Personal Area Network is only a prototype technology, however with the increasing speed of developing technology it will probably be implemented into everyday lives, in the not so distant future.

The basic idea is that due to the natural salinity of the human body it is an excellent conductor of electrical current. PAN technology takes advantage of this conductivity by creating an external electric field that passes an incredibly tiny current through the body, over which data is carried. The current used is one-billionth of an amp (one nanoamp), which is lower than the natural currents already in the body. The speed at which the data is transmitted is equivalent to a 2400-baud modem. Theoretically, 400,000 bits per second could be communicated using this method.

PAN developed because of the shortcomings of various conventional methods to facilitate intercommunication between personal communication devices. For example, wiring all these devices together would be cumbersome and constrictive to the user. Infrared communications of information, used on TV remote controls, requires direct lines of sight to be effective. Radio frequencies (such as those used with automated car locks) could jam or interfere with each other, or be imprecise in crowded situations.

The PAN system consists of battery operated transmitters and receivers that are electrically isolated and have a pair of electrodes. The PAN transmitter capacitively couples a modulating picoamp displacement current through the human body to the receiver. The return path is provided by the 'earth ground,' which includes all conductors and dielectrics in the environment that are in close proximity to the PAN devices. The earth ground needs to be electrically isolated from the body to prevent shorting of the communication circuit.

It is not difficult to see that this technology has a mind-boggling array of possible applications. You could exchange electronic business cards by simply shaking hands; it would effectively eliminate the need for smart cards and other forms of identification. You could have large scale computing at your fingertips. A watch is too small to contain a full featured multimedia computer, but it is large enough to contain a microphone, display and a camera. Such an I/O enriched watch could be networked to a fast, powerful computer located in your back pocket or in a waist pack. Data could be uploaded from soles of your shoes and transferred to any computing device on your body as you walk! This research has uncovered a novel means to perform local communication using electric fields.

However the trade-off among cost, speed, size, power, and operating range must be further studied and quantified in order to engineer practical PAN devices. A number of other issues such as protocol and privacy are yet to be addressed. But the concept of the Personal Area Network takes us at an exponential pace towards a world of complete interconnectivity - the ultimate goal of modern day communication.