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Monday, May 27, 2002
Lead Article

Bluetooth revolution
Hirdepal Singh

IMAGINE you could be sending e-mail using your laptop through mobile phone in your pocket without making any connection between laptop and mobile. All this would be possible through a revolutionary technology called Bluetooth, named after King Harald Bluetooth who lived in Denmark between 910-940 AD.

Bluetooth is actually a standard or wireless communication between devices in a personal area network (PAN) using radio frequency for a short range (round 10 meters). Therefore, any two devices that follow the standard can communicate and exchange data between each other without the need of any physical connection to be made between them. A group of Bluetooth-enabled devices like mobile phone, a digital camera, a handheld device etc can instantly form a network with each other as soon as they are switched on.


Bluetooth technology

Bluetooth is high-speed, low-power microwave wireless link technology. Unlike infrared, Bluetooth does not require line-of-sight positioning of connected units. When one Bluetooth device comes within the range of another, they automatically exchange address and capability details. They can then establish 1 megabits link with security and error correction, to be used when required. The protocols will handle both voice and data, with a flexible network topology. This technology achieves its goal by embedding tiny, inexpensive, short-range transceivers into the electronic devices that are available today. The radio operates on the globally available unlicensed radio band 2.45 GHz. The Bluetooth module can either be built into electronics devices or used as an adaptor. For instance, in a PC they can be built in as a PC card or externally attached via USB port.
Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to-point or multipoint. The maximum range is 10 metres but can be extended upto 100 metres by increasing the power. Bluetooth devices are protected from radio interference by changing their frequencies arbitarily upto a maximum of 1600 times a second, a technique known as frequency hopping. They also use three different but complimentary error correction schemes. Bluetooth radio technology provides a universal bridge to existing data networks, a peripheral interface and a mechanism to form small private ad hoc grouping of connected devices away from the fixed network infrastructures.

Designed to operate in a noisy radio frequency environment, the Bluetooth radio uses a fast acknowledgement and frequency-hopping scheme to make the link robust. Bluetooth radio modules avoid interference from other signals by hopping in the same frequency band; the Bluetooth radio typically hops faster and uses shorter packets. This makes the system more robust than other systems.

An interesting aspect of this technology is the instant formation of networks once the Bluetooth devices come in the range each other. A piconet is a collection of devices connected via Bluetooth technology in an ad hoc fashion. A piconet can be a simple connection between two devices or more than two devices. Multiple independent and non-synchronised piconets can form a scatternet. Any of the devices in a piconet can also be a member of another by means of time multiplexing. This means a device can be a part of more than one piconet by suitably sharing the time. The Bluetooth system supports both, point-to-point and point-to-multipoint connections. When a device is connected to another device, it is a point-to-point connection. If it is connected to more than one, it is a point to multipoint connection. Several piconets can be established and linked together on ad hoc basis, where each piconet is identified by a different frequency hopping sequence. A piconet starts with two connected devices such as a portable PC and cellular phone and may grow to eight connected devices. All Bluetooth devices are peer units and have identical implementations. However, when establishing a piconet, one unit will act as a master and the other as slave for the duration of the connection. In a piconet there is a master unit whose clock and hopping sequence are used to synchronise all other devices in the piconet. All the other devices in a piconet that are not the master are slave units. A 3-bit MAC address is used to distinguish between units participating in the piconet. The Bluetooth air interface is based on a nominal antenna power of 0dBm.

Specifically, Bluetooth has applications in at least three important computing domains:

(i) Home Networking.

(ii) Automobile Network Solutions

(iii) Mobile e-business.

Bluetooth has an enormous potential in moving and synchronising information, devices in a localised setting.

By installing a Bluetooth network in office, we can do away with the complex and cumbersome task of networking between computing devices. We no longer have the need to go in for structured cabling, hubs, line terminal servers etc, but still have the power of connected devices. Bluetooth technology connects all office peripherals wirelessly. Connect your PC or notebook to printers, scanners and faxes without the ugly and troublesome cable attachments. It increases our freedom by connecting the mouse and keyboard wirelessly to our computer.

Three-in-one phone

A Bluetooth capable mobile phone could be used as a standard cellular phone. Using a wireless service provider as a carrier, it could also be used like a cordless phone through a Bluetooth voice access point in the home. Using the home’s normal wired telephone system, it could also be used as an intercom with direct point-to-point voice communications within the home without involving any carrier.

If our digital camera is Bluetooth enabled, we can send still or video images from any location to any location without the hassle of connecting the camera to the mobile phone or the wireline phone.

In meetings and conferences, we can transfer selected documents instantly with the selected participants and exchange electronic business cards automatically without any wired connections.

Connect our wireless headsets to our mobile phone to keep our hands free for more important work.

The mobile Bluetooth-enabled headset is a lightweight, wireless mobile phone headset with a built-in Bluetooth radio chip that acts as a connector between the headset and the Bluetooth plug on the mobile phone. When phone rings, we can answer, by simply pressing a key on the headset. If we want to make a call, press key on the headset and use voice recognition to initiate the call. The phone can be up to 10 metres away, in a briefcase or in your pocket or even in another room while we speak and enjoy complete mobility without cables dangling around. This Bluetooth headset sits comfortably on either ear and can be used with many new models of mobiles like Ericsson T28, T28 World and R320 cellular phones. Nokia has released a Bluetooth phone package that includes a Nokia 7190, GSM 1900 and a Nokia connectivity card DTL-1 to enable Bluetooth connection between phone and laptop. Nokia and Fuijifilm have been developing a prototype mobile imaging technology, allowing a modified Nokia 9110 communicator containing a Bluetooth chip to receive images taken on a Bluetooth equipped Fujifilm digital camera to send them through e-mail anywhere.

With this technology we can think of a connected world of electronics devices and appliances around us. We click on an icon for a device and we are linked to it automatically and transparently.