Panning for data with personal-area networks

The best-known personal-area network (PAN) is Bluetooth. Named after a 10th century Danish king, Bluetooth is a system that changes frequencies from moment to moment using a technique called frequency-hopping and has an effective range of about 10 meters, but occasionally farther. Bluetooth is just now beginning to appear in computer systems, especially notebooks, as a replacement for physical cables and for infrared connections, which are limited to line of sight. Bluetooth devices “find” one another when they’re in range and automatically set up a background connection.

[For more information on Bluetooth, see Computerworld‘s QuickStudy, June 12, 2000, or the Web site of Bluetooth SIG Inc.]

There has been some concern that Bluetooth signals may conflict with those using another frequency-hopping protocol, 802.11b wireless Ethernet, but it isn’t a certainty.

Bluetooth is still unproven in the marketplace, although virtually every computer maker seems interested. The price is currently rather steep, adding $100 to $200 to the cost of a notebook, but when the needed chips drop in price, Bluetooth may well become a standard feature of most systems, just as Universal Serial Bus has.

Many noncomputer uses for Bluetooth are expected to develop, including such things as wireless earpieces for cell phones, keyboards and other input devices, and televisions.

If there are any serious problems with Bluetooth, they’re security and speed. Bluetooth seems to rely on its limited range as a significant security mechanism, and it’s not comforting to think of an executive with a Bluetooth-equipped notebook sitting in an airport while his system is looking to connect with other Bluetooth devices. While other security systems could be piggybacked on Bluetooth, it’s an awkward solution at best.

Speed is another matter. At less than 1M bit/sec., Bluetooth doesn’t have enough bandwidth for serious communications. This will be addressed in the near future by a much faster and newer technology called Ultra-Wideband (UWB), which is actually an offshoot of military radar. UWB has not yet been approved by the Federal Communications Commission, and no standard yet exists. However, FCC approval is expected within the next few months, and an IEEE group is working on the standard, which will be labeled 810.15.3. UWB will offer a working range of about 10 meters, like Bluetooth, but it will have speeds approaching 100M bit/sec. and significantly lower power consumption to boot.

Another PAN worth mentioning is the piconet, wherein networks of as many as seven nodes can be established, with all communications going through a single host. If that host is connected to other piconet hosts, the resulting “scatternet” lets groups communicate with other groups.