[attachment=12041]
Introduction to Bluetooth Technology
Bluetooth is a radio frequency specification for short range, point to point and point to multi point voice and data transfer. Bluetooth technology facilitates the replacement of cables normally used to connect one device to another by a short range radio link. With the help of blue tooth we can operate our keyboard and mouse without direct connection of CPU. Printers, fax machines, headphone, mouse, keyboard or any other digital devices can be part of Bluetooth system.
In spite of facilitating the replacement of cables, Bluetooth technology works as an universal medium to bridge the existing data networks, a peripheral interface for existing devices and provide a mechanism to form short ad hok network of connected devices away from fixed network infrastructures.
Due to their independence on short range radio link, Bluetooth devices do not require a line of site connection in order to communicate. Therefore a computer can print information on a printer if printer is in inside the room. Two blue tooth devices can talk to each other when they come within range of 10 meters to each other.
Bluetooth technology represents an opportunity for the industry to deliver wireless solutions that are ubiquitous across a broad range of devices.
Why it’s name is Bluetooth?
While many new technologies bear technical names, like RS-232 or IEEE
802.11b, Bluetooth, the wireless technology, is different.
Bluetooth was named for the 10th Century Viking king , Harald Blatand
(A.K.A., Bluetooth) who peacefully united all the tiny island kingdoms of
Denmark, southern Sweden, and southern Norway into one country . In
keeping with its namesake, Bluetooth, the new low-cost radio technology, is
designed to unite or connect all different types of devices to effectively work
as one. By uniting devices, Bluetooth eliminates the need for cabling in a
wide range of products, including cellular phones, PCs, headphones, audio
equipment, printers, and many more.
Bluetooth Definitions
• Piconet: Devices connected in an ad hoc fashion, that is, not requiring predefinition and planning, as with a standard network. Two to eight devices can be networked into a piconet. It is a peer network, that is, once connected, each device has equal access to the others. However, one device is defined as master, and the others as slaves.
• Scatternet: Several piconets may form a larger scatternet, with each piconet maintaining independence.
• Master unit: The master in a piconet whose clock and hopping sequence synchronizes the other devices.
• Slave unit: Devices in a piconet that are not the master.
• MAC address: Three bit address that distinguishes each unit in a piconet.
• Parked units: Piconet devices that are synchronized but don't have MAC addresses.
• Sniff and hold mode: Power-saving mode of a piconet device.
How Bluetooth Technology Work
The technology of Bluetooth centers around a 9mm x 9mm microchip, which functions as a low cost and short range radio link. Bluetooth Technology provide a 10 meter personal bubble that support simultaneous transmission of both voice
and data for multiple devices. Up to 8 devices can be connected in a piconet, and uo to 10 piconets can exist within the 10 meter bubble. Each piconet support
up to 3 simultaneous full duplex voice devices.
The gross data rate is 1 Mb/s, but the actual data rate are 432 kbps for full
duplex transmission,721/56kbps for asymmetric transmission, and 384 kbps for
tms2000 transmission.
Bluetooth wireless technology is designed to be as secure as a wire with up to 128-bit public/private key authentication, and streaming cipher up to 64 bit based on a5 security.
Transmission types and rates :
The baseband (single channel per line) protocol combines circuit and packet switching. To assure that packets do not arrive out of order, slots (up to five) can be reserved for synchronous packets. As noted earlier, a different hop signal is used for each packet. Circuit switching can be either asynchronous or synchronous. Up to three synchronous (voice) data channels, or one synchronous and one asynchronous data channel, can be supported on one channel. Each synchronous channel can support a 64 Kb/s transfer rate, which is fully adequate for voice transmissions. An asynchronous channel can transmit as much as 721 Kb/s in one direction and 57.6 Kb/s in the opposite direction. It is also possible for an asynchronous connection to support 432.6 Kb/s in both directions if the page link is symmetric.