Bluetooth Techology

He died during a battle in 986AD. Although he died without unifying all the Nordic nations he became synonymous with the unification of telecommunication and computing. Hence Bluetooth is based on Runes surrounding the legend of Harald Bluetooth. It is built based on the aim to make communication a personal space to mankind. The Bluetooth connection takes place in real time, passing data instantaneously.


Bluetooth technology is designed in a way that it operates at 2.4GHz(i.e.) within a short range of wireless communication. The range of Bluetooth is about 10metres, which is approximately 30 feet. It is designed such that it’s light and portable. It contains standards and protocols that makes it mobile, robust, reliable. It is not limited to one manufacturer. The Bluetooth has replaced cables which when compared is very cost effective. The Bluetooth has to be resilient to the interference caused. When Bluetooth is made use for mobile devices it designed to be compact, lightweight, lower power and easy to use. It has a built in mechanism to inquire for devices, connect to them and once connected discover the services they possess in their database.


A Simple procedure that makes you understand how Bluetooth connection is established:


The master inquires to discover devices available to connect.


The slave listens for an inquiry from the master by entering into the inquiry scan mode.


When an inquiry is received, the slave responds to the master with a Frequency Hop Synchronization packet (FHS). The FHS contains information that helps to create a connection to the device; the information includes Bluetooth address and class of device.


The master collects the FHS information from each device that is being discovered. To connect to one of these devices the master makes use of the Bluetooth address and goes into page mode and pages the device.


The slave being paged has to be in page scan mode to enable a connection to the master.


For majority of the countries the Industrial, Scientific and Medical (ISM) band used by Bluetooth is available from 2.40-2.4835 GHz. Frequency Hopping Spread Spectrum (FHSS) techniques are made use by Bluetooth in order to improve its immunity from interference. Bluetooth enables adequate frequency coverage with test sequence.


Bluetooth Special Interest Group (SIG) works to promote, shape and define the specification and position Bluetooth in the market place. SIG enables protocol definitions for ensuring interoperability. For higher layers protocols it ensures bearer services and host control interface.


Communication using Bluetooth technology is encrypted for security. When two Bluetooth devices try to establish a link, the foremost thing they do is to confirm their identities by exchanging their keys. The two devices will not be able to communicate if the keys don’t match.


The Bluetooth core specification describes the protocol; the profile document helps applications development. It describes implementation schemes and highlights the core Bluetooth protocol supporting the profile. The example of profiles is a wireless headset for mobile phones. The headset profile is made use as the core specification. The headset profile is built from SPP (Serial Port Profile) and GPP (Generic Access Profile). The GAP defines the procedures that deal with the device discovery and link management.


Blue tooth is applied as access points allowing mobile device connection services e.g. PSTN or LAN services. It allows Mobile phone link to Laptop PCs. It is used by PDA, palmtop and desktop PCs. It ensures communication compatibility worldwide by being made use by cell phones, cordless phones, microwaves, and Wi-Fi technology.