Understanding Bluetooth Technology:

What is Blue Tooth?

Bluetooth is a wireless standard for interconnecting communication devices and accessories using short-range, low power, cheap wireless radios. This Blue Tooth project was formed by L.M. Ericsson Company with IBM, Intel, Nokia and Toshiba in 1994. Bluetooth specification is for a complete system, starting from physical layer to the application layer.

What Bluetooth can provide?

1. Eliminates cables linking for computers to printers, keyboards and the mouse.

2. You can on or off home appliances like washing machine etc., from Remote place and you can also monitor the activity happening.

3. Music can be downloaded into MP3 players by hooking them to other machines.

4. Calls can be made from wireless headset to a remote cell phone.

Bluetooth Architecture :

Piconet is the basic unit of Bluetooth system. This Piconet has a master node and equipped with seven active slave nodes with in a distance of 10 meters.

An interrelated collection of Piconets is called Scatternet. Two Piconets can be connected with a bridge slave node, and these Piconets can exist within the same room. The master will switch the 255 parked nodes in the net to a low -power state. This is done to reduce drain on their batteries. The device can only respond to beacon signal from master, and cannot do anything else other than this, in parked state. All Communication is between master and slave, direct slave to slave communication is not possible. Piconet is a centralized Time Division Multiplexing (TDM). Here the master will decide which device gets to communicate in which time slot, by controlling the clock.

Bluetooth Applications :

Bluetooth specification says it should support 13 specific applications. These applications are called profiles which are listed below :

1. Synchronization : Permits a PDA to synchronize with another computer.

2. Fax : Alloy - a mobile fax machine to talk to a mobile phone.

3. Intercom : Digital walkie-talkie.

4. Headset : Hands-free voice communication is provided.

5. Generic Access : Link Management Procedures.

6. Serial Port : Serial Port cable replacement.

7. Service discovery : Protocol for discovering offered services.

8. File Transfer : Provides a more general file transfer facility.

9. LAN Access : Protocol between a mobile computer and a fixed LAN.

The Bluetooth Protocol Stack :

The basic Bluetooth protocol architecture does not follow the OSI model. TCP/IP model etc.,

It is given below :