Personal Area Networks: Say It And You Are Connected!

"A gentle touch or a warm hug. These are not just ways of showing emotions. Next time you kiss somebody you could also be exchanging information. Yes, transferring data. How unromantic!"

Have you ever wondered how much time we typically spend in a day, trying to be in contact with our families and business contacts? How much time do we spend accessing information that is so critical in our day to day activity? In order to be in contact all the time and to be able to access any information anywhere and any time we carry so many accessories all the time! Typically one may be carrying a PDA, a mobile phone, a pager, a notebook computer, a personal stereo etc.

To be able to do so may be very essential but all this comes at a premium. The problems are the complexities involved with using so many different devices, maintaining a sync between all these devices and, of course, the inconvenience of having to carry all these devices. A person who carries a watch, pager, cellular phone, personal stereo, personal digital assistant (PDA), and notebook computer is carrying five displays, three keyboards, two speakers, two microphones, and three communication devices. [1] The duplication of I/O components is in part a result of the inability of the devices to exchange data. With proper networking these devices can share I/O, storage, and computational resources.

So, the problem is all about the inability of all these devices to network with each other seamlessly and transparently. I am sure you are not thinking that I am proposing a scenario wherein we connect all these devices using wires and achieve the goal of networking all these devices! The solution I want to talk about is based on the following considerations:

1. Remove the IO and storage redundancy
2. Achieve an instant and transparent way of interdevice communication
3. Security: The data communication between these devices must be secure and should be limited to the intended set of devices
4. The power consumption overhead should be very small or zero! (Yes, zero.. I'll talk about it later in the article). We don't want that we end up carrying yet another thing in our pocket: a battery!
5. Ability to expand the scope of communication between devices to other devices like a desktop computer etc.

What are the solutions available?

One way of transferring data between two devices is using RF (Radio Frequency). As the growth of wireless services (e.g., cellular phones, pagers, and radio frequency local area networks [RF LANs]) fills up the limited RF spectrum, near-field communication offers an alternative to congesting the airwaves with data. Also with RF communications there would always be the associated issues of security. Far field, RF communications are always susceptible to eavesdropping and interference because the isotropic properties of a radio transmitter. Power consumption is also an issue. There are also infrared (IR) solutions available but IR solutions are not practical for communication between devices hidden in wallets, pockets etc. Focused IR relies on line-of-sight transmission, which is difficult to maintain with body-based devices that are constantly in motion. Diffused IR relies on a wide-angle beam of high optical power requiring hundreds of milliwatts. Personal area networks, work on the near field, electric field sensing. Electrostatically coupled PAN devices use the body as a "wet wire" and can operate on several milliwatts of power.

Next: How Did PANs Come Into Existence?