How does Bluetooth Work?

What’s in the name?
Before explaining how bluetooth works, I thought of telling you the story of the birth of its name, Bluetooth! The word Bluetooth was borrowed from the 10th century, second King of Denmark, King Harald Bluetooth. He was well known for bringing together Scandinavia. He played a major role in uniting Denmark and Norway and in the introduction of Christianity. To show the significance of bringing together different devices and enabling communication between them, Bluetooth technology got its name after this king.

Bluetooth is a technology, whereby, devices communicate wirelessly to achieve data transfer at the rate of 720kbps within a range of 10 to 100 meters. It operates in the unlicensed ISM (Industrial Scientific and Medical) band at 2.4 gigahertz.

How does blutooth work?
Now, about how bluetooth works … Bluetooth Special Interest Group manages and maintains the Bluetooth Standard. IEEE has accepted it as 802.15la standard. Bluetooth was developed with a purpose of creating a single digital wireless protocol, capable of connecting multiple devices and getting over the synchronization issues. It enables short-range wireless communication thus replacing wires connecting the electronic devices.

The Bluetooth RF transceiver lies at physical layer. There are 79 bluetooth channels spaced 1MHz apart. A spread spectrum technology is used at the physical layer. Both voice and data transmissions over short distances are possible, creating wireless PANs.

A bluetooth device consists of an adapter. A Bluetooth adapter can be built into a device or can be in the form of a card that connects to a device. Instructions are embedded into the device, which enable it to communicate with other devices.

When devices come in each other’s radio range, their link managers discover each other. Link management protocol (LMP) engages itself in peer-to-peer message exchange. LMP layer performs link setup and negotiation of packet size. Segmentation and reassembly of packets is done, if needed.

Service delivery protocol enables a bluetooth device to join a piconet. A device inquires what services are available with the piconet. Bluetooth GlobalID is exchanged between the devices. Their profiles are matched and a connection is setup.

Bluetooth uses frequency hopping in timeslots, which means that the bluetooth signals avoid interference with other signals by hopping to a new frequency after transmission or reception of every packet. One packet can cover up to five time slots.

Bluetooth can support an asynchronous data channel, or up to 3 simultaneous synchronous voice channels, or a channel, which concurrently supports asynchronous data and synchronous voice.

Bluetooth technology makes use of the concept of master and slave. Devices have to wait until the master allows them to talk! One master and up to seven slaves employ a star topology to form a piconet.

Bluetooth Application Models

File Transfer : -This model talks of an object transfer or transfer of files between devices.

Internet Bridge : -In this model, a cordless modem acts as a modem to a PC and provides dialup networking and faxing.

LAN Access : -Multiple data terminals use a LAN access point (LAP) as a wireless connection to an Ethernet LAN.

Synchronization : -Synchronization model provides a device-to-device synchronization of data.

Headset : -It is wirelessly connected and can act as an audio input-output interface of remote devices.

Bluetooth Buzzwords

Piconet : -A group of devices connected by means of Bluetooth technology in an ad hoc manner is known as a piconet. There can be a maximum of 8 devices forming one piconet. For the duration of a piconet connection, one device acts as the master and others act as slaves in order to synchronize.

Scatternet : -A scatternet is composed of two or more independent piconets. This brings about a communication between piconets.

Master unit : -Its clock and hopping frequency are used to synchronize other devices in the piconet. The master device numbers the communication channels.

Slave unit : - The slave units act in co-ordination with the master.

Bluetooth Applications

1. Bluetooth has a wide range of applications. Wireless communication between a mobile phone and a handset is possible by way of bluetooth.
2. Computers can form a wireless network in a limited space and when bandwidth requirement is less.
3. Unwired communication between the input and output devices of a computer is possible by means of bluetooth technology.
4. Transfer of files and data between devices with OBEX is achieved. OBEX is a session protocol that provides the functionality of HTTP in a lighter fashion.
5. Some game consoles use bluetooth for their wireless controllers.
6. Bluetooth-enabled mobile phones and modems can make possible, dial up Internet connections for PCs or PDAs.

Why Headsets?
When on wheels, when driving, you can make and receive calls due the hands free headset. Some recommend headsets to minimize the radiations pumped into your brain. Even if you have several different Bluetooth equipped phones, a headset should work with all of them conveniently. If you replace your phone, the headset will work just fine with the new handset. A bluetooth headset can be used to connect to your computer and other such devices as well!

Bluetooth GPS…What it is…
Bluetooth GPS can work as your travel escort! You carry some directions or maps in your PDA’s memory. Even better is to use Belkin GPS Receiver. This receiver is technologically advanced to receive satellite reception. It supports voice and visual direction. The built-in software can create maps for you. Where does bluetooth come into picture? It helps make easy the conversion of your PDA to a GPS receiver.

Advantages of Bluetooth
There are numerous advantages of Bluetooth.
Firstly, it eliminates all the cords used in connections. ! Line of sight is not required. The word ‘unwired’ is in some way synonymous to the word ‘uncluttered’!

Secondly, with bluetooth headsets, you can use your cell phone without the use of your hands. That makes it safe to talk on phone while your hands are engaged in other activities. Due to bluetooth, you are not required to be physically close to the device you are using.

Thirdly, Bluetooth devices are fairly inexpensive. There is no special cost incurred in using the service.

The next concern is interoperability. Bluetooth is a standardized specification. Bluetooth enabled devices are highly compatible. They understand each other without human intervention. When they enter a range of one another, they start communicating on their own. The process of setup is automatic.

Then comes efficiency! Bluetooth uses low power signals, thus requiring less energy. Due to spread-spectrum frequency hopping, interference with other wireless devices stays away.

Bluetooth Special Interest Group has been working on upgraded versions, which can yet remain backward compatible.

Moreover, bluetooth is secure. Strict security rules will not allow the devices to communicate unless pre-approved by you. So it is you, who is the controller of communication!

Ericsson was the first to develop the Bluetooth specification. Many companies are now making their products capable to use it. I think bluetooth technology is a complete package of virtues like feature simplicity, inexpensiveness and the need of least human involvement in its implementation. Bluetooth is here to stay for years to come!