Introduction to Bluetooth
Bluetooth is an always-on, short-range radio hookup that resides on a microchip. It was initially developed by Swedish mobile phone maker Ericsson in 1994 as a way to let laptop computers make calls over a mobile phone. Since then, several thousand companies have signed on to make Bluetooth the low-power short-range wireless standard for a wide range of devices. Industry observers expect Bluetooth to be installed in billions of devices by 2005 (Business Week, 18 September 2000).
The Bluetooth standards are published by an industry consortium known as the Bluetooth SIG (special interest group).
The concept behind Bluetooth is to provide a universal short-range wireless capability. Using the 2.4 GHz band, available globally for unlicensed low-power uses, two Bluetooth devices within 10 m of each other can share up to 720 Kbps of capacity. Bluetooth is intended to support an open-ended list of applications, including data (such as schedules and telephone numbers), audio, graphics, and even video. For example, audio devices can include headsets, cordless and standard phones, home stereos, and digital MP3 players. Following are some examples of the capabilities that Bluetooth can provide consumers:
Make calls from a wireless headset connected remotely to a cell phone.
Eliminate cables linking computers to printers, keyboards, and the mouse.
Hook up MP3 players wirelessly to other machines to download music.
Set up home networks so that a couch potato can remotely monitor air conditioning, the oven, and children's Internet surfing.
Call home from a remote location to turn appliances on and off, set the alarm, and monitor activity.
Bluetooth is designed to operate in an environment of many users. Up to eight 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.
Bluetooth provides support for three general application areas using short-range wireless connectivity:
Data and voice access points. Bluetooth facilitates real-time voice and data transmissions by providing effortless wireless connection of portable and stationary communications devices.
Cable replacement. Bluetooth eliminates the need for numerous, often proprietary cable attachments for connection of practically any kind of communications device. Connections are instant and are maintained even when devices are not within line of sight. The range of each radio is approximately 10 m, but can be extended to 100 m with an optional amplifier.
Ad hoc networking. A device equipped with a Bluetooth radio can establish instant connection to another Bluetooth radio as soon as it comes into range.