Bluetooth Technology

Bluetooth is basically a cable-replacement technology. Consider the current standard computer set up; we have a keyboard connected to the computer, as well as a mouse, a monitor, possibly a printer, a scanner, and so on. These are usually all connected to the PC by cables. A Bluetooth chip is designed to replace cables by taking the information normally carried by a cable and transmitting it at a special frequency to a receiver Bluetooth chip in the computer, phone, printer and any portable devices. Bluetooth is a standard for a small, cheap radio chip to be plugged into computers, printers, mobile phones and devices. The low cost of a Bluetooth chip and its low power consumption make it possible to place one anywhere. We can have Bluetooth chips in freight containers to identify cargo when a truck passes through customs or drives into a storage depot. A headset that communicates with a mobile phone in our pocket The Bluetooth technology provides a solid mechanism for forming small wireless networks of Bluetooth-equipped products on an ad hoc basis. It can also serve as a wireless bridge to existing data networks.

Bluetooth-enabled products will automatically seek each other out and configure themselves into networks most often with just two nodes. Even though such networks are very small, they are becoming highly beneficial. They can forward e-mail received on a cellular phone in a person's pocket to the notebook or laptop computer in his or her briefcase; they can download data from a digital camera to a PC or cell phone or they can alert their owners as they pass a Bluetooth-enabled vending machine. With Bluetooth technology, a Bluetooth-linked cell phone or similarly equipped PDA can automatically synchronize with our desktop PC whenever we pass it within the specified Bluetooth range. Bluetooth can serve as a means for connecting laptop computers or other devices to the public Internet in airport lounges and conference centers through permanent access points. It can also enable its user to exchange business cards with everyone passed on the street through a Bluetooth-enabled Palm.

Bluetooth technology is expected to make its debut in cellular phones and PDAs and is to move slowly and steadily into notebook and laptop computers, printers, scanners, digital cameras, household appliances, security/remote access, games, toys and more.

The Bluetooth Special Interest Group (SIG) has more than 2000 organizations that are currently developing Bluetooth-enabled products under a specification developed by this SIG. The IEEE 802.15 Personal Area Network (PAN) working group has made Bluetooth the foundation for a range of consumer network products.

Bluetooth's maximum data rate is listed at 1 Mbps, but it is closer to 780 Kbps when protocol overhead is taken into account. This positions Bluetooth between telephone modems (56Kbps) and digital subscriber lines (DSL) or cable modems. However, in practice, Bluetooth's 780 Kbps is shared among communicating devices so that actual throughput depends on the number of Bluetooth devices sharing a commmon channel. A significant boost in performance is anticipated with next-generation Bluetooth targeting the 5 GHz band.

Ericcson, which took the initiative in developing Bluetooth technology, has come out with a number of innovative Bluetooth products, including a headset, a PC card for laptops and PDAs, and a couple of Bluetooth cell phones. Telecommunication companies such as Nokia, Fujifilm, Sonera etc are also working hard for rolling out Bluetooth-enabled products and their accessories.

Bluetooth Basics

A Bluetooth radio consists of a radio-frequrency (RF) transceiver portion, a baseband link control unit, and the associated link management software, plus an antenna subsystem. The transmitter mixes the baseband information with the frequency-hopping local oscillator to generate a frequency-modulated carrier. In alternate slots, the receiver downconverts and demodulates the RF signal, using the same local oscillator.

The radio uses frequency-hopping spread-spectrum technology to support both point-to-point and point-to-multipoint connections. Bluetooth operates in the crowded 2.4 GHz industrial, scientific and medical(ISM) radio waveband, available worldwide without a license. In order for Bluetooth to be available worldwide, regulators have agreed to let Bluetooth use the frequency range 2,400 MHz to 2,483.5 MHz.

Within the current specification, up to eight Bluetooth-enabled devices can automatically configure themselves into a piconet.

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