Bluetooth a boon for wireless devices

Imagine you are going to a meeting with your cell phone in your briefcase and your notebook computer in tow. You open the computer and, without plugging in to anything, begin receiving e-mail. In the meeting, you also receive files from others in the room without receiving e-mails, or you send files without e-mail.

"Beam me up Scotty"? No - in the first instance, your notebook is communicating with your cell phone, which in turn is communicating with a wireless network. In the second, you are communicating directly with others in the meeting, notebook to notebook. Both are possible through a revolutionary new radio chip developed through a collaboration of the computing and communications industries, code-named Bluetooth.

Bluetooth is also the official name of a specification that has become the fastest growing technology standard ever. Put simply, Bluetooth is a specification for wireless technology, a global standard that lets devices communicate with each other using a secure radio frequency.

Bluetooth-enabled portable computers, mobile phones, office equipment, household appliances and more can communicate at short ranges without the burden of cables - securely, inexpensively, at a high rate of data transmission and without line-of-sight requirements.

For instance, if you're using a mobile phone and need a phone number, you can synchronize with your phone book stored on your desktop computer. Bluetooth technology can even be used to connect office devices such as printers.

To exploit its potential and further Bluetooth as a global standard, an organization was formed in 1998 by world leaders in mobile technology. The founding companies - IBM, Ericsson, Nokia, Intel and Toshiba - created the Bluetooth Special Interest Group.

The Bluetooth device is a small, low-powered radio on a chip that communicates with other Bluetooth-enabled products. Because it is a radio, Bluetooth eliminates the necessity for cables to connect portable computers, personal digital devices, cellular phones, printers, fax machines and the like. Bluetooth-enabled devices can connect on a one-to-one or one-to-many basis.

Bluetooth supports voice and data communications, so it can be extended into hands-free voice communications for wireless phones in vehicles. Bluetooth technology uses the 2.4-GHz radio band, which is unlicensed and available almost worldwide.

Bluetooth is also a low-power radio module that can be built into a plethora of devices. It supports data speeds of up to 721K bit/sec (including a 56K bit/sec back channel) and three voice channels.

Bluetooth has been designed to operate in an environment of many users. Up to eight users or devices can communicate in a small network called a piconet. Ten of these piconets can coexist in the same coverage range of the Bluetooth radio. To provide security, each link is encoded and protected against eavesdropping and interference.

For network administrators, these Bluetooth piconets create benefits and challenges. Within a piconet, services can be offered to mobile users without the normal configuration requirements. For instance, conference rooms could have Bluetooth-enabled printers installed and a mobile user could use them without configuring the printer.

However, if an enterprise has wireless LAN technology (IEEE 802.11b) deployed, the Bluetooth technology and wireless LANs may interfere with each other. To minimize this interference, the placement of Bluetooth piconets within a larger wireless LAN is the challenge confronting the LAN administrator.

While the computing devices can be enabled with Bluetooth without the need for a PC card or option bay, antenna design will be one focus of the future. It would be highly desirable to incorporate the radio and antenna into the device. Another area of future work is power management, particularly in mobile devices powered by batteries. The power consumption of Bluetooth devices needs to be such that it is not a burden on the battery lifetime.

But in spite of the necessary work, Bluetooth represents a future technology freeing devices of cable and making the world a more mobile place.

Frazier is a senior engineer at IBM. He can be reached at bluedvl@us.ibm.com

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