Bluetooth is a method for data communication that uses short-range radio links to replace cables between computers and their connected units. It was started by a SIG comprising of IBM, Intel, Nokia, Toshiba and Ericsson.
The Aim of Bluetooth 1.Global usage 2.Voice and data handling 3.The ability to establish ad-hoc connections 4.The ability to withstand interference from other sources in open band 5.Very small size, in order to accommodate integration into variety of devices 6.Negligible power consumption in comparison to other devices for similar use
The etymology of the name Bluetooth comes from a tenth century Scandinavian king, Harald Blaatand, who managed to unite several unruly kingdoms. Thus, Bluetooth is a reference to the taming of a myriad of unruly competing standards by defining one worldwide specification
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.
The basic part of the Bluetooth system consists of the radio chip and controller. The Link Manager (LM) is software . The hardware underlying the LM is the link controller (LC). These two perform the following tasks:
1. Sending and receiving data.
2. Paging and inquiries.
3. Setting up connections.
5. Negotiating and setting up link types, i.e., SCO or ACL.
1. Radio Layer : The radio module in a Bluetooth device is responsible for the modulation and demodulation of data into RF signals for transmission in the air. The radio layer describes the physical characteristics a Bluetooth device’s receiver-transmitter component must have.
2 . Baseband and LC layer : The baseband portion of the layer is responsible for properly formatting data for transmission to and from the radio layer. In addition, it handles the synchronization of links. The link controller portion of this layer is responsible for carrying out the link manager’s commands and establishing and maintaining the link stipulated by the link manager .
3. Link manager: It translates the host controller interface (HCI) commands it receives into baseband-level operations. It is responsible for establishing and configuring links and managing power-change requests, among other tasks.
4. The HCI (host controller interface) layer: This acts as a boundary between the lower layers of the Bluetooth protocol stack and the upper layers.
6 . Service Discovery Protocol(SDP): It defines actions for both servers and clients of Bluetooth services. The specification defines a service as any feature that is usable by another (remote) Bluetooth device. A single Bluetooth device can be both a server and a client of services.
7. RFCOMM : It connects to the lower layers of the Bluetooth protocol stack through the L2CAP layer.
8. OBEX (object exchange): It is a transfer protocol that defines data objects and a communication protocol two devices can use to easily exchange those objects. A Bluetooth device wanting to set up an OBEX communication session with another device is considered to be the client device.
1. Bluetooth-mouse and keyboard could be used at a further distance from a monitor.. This would reduce eye-strain and exposure to electromagnetic radiation from the monitor.
2. A traveling businessman could ask his laptop computer to locate a suitable printer as soon as he enters a hotel lobby, and send a printout to that printer when it has been found, and replied in a positive manner.
3. Cable-less connection to printers and faxes .
4. Cable-less connection to digital cameras and video projectors.