Brief Introduction About Bluetooth

- Sep 03, 2018-


Bluetooth is a wireless communication technology that allows electronic devices


to communicate over small distances and, just as Wi-Fi, operates on the 2.4


GHz ISM frequency band. Despite operating on an open band, the   Bluetooth 


technology is regulated by the “Bluetooth Special Interest Group” (SIG) and


was standardized by IEEE as IEEE 802.15.1, even though it no longer maintains


the standard. Common examples of Bluetooth devices are Bluetooth


speaker,Bluetooth headsets, game controllers, wireless keyboards and mice 


and Bluetooth beacon.


Bluetooth uses 79 channels to transmit data, starting with the first channel at a


frequency of 2402 MHz and continuing up to the last one at a frequency of 2480 


MHz in 1 MHz increments.In order to avoid interference from other RF signals,a


technique known as frequency hopping where data is transmitted over one of


the available channels for a small period of time and resent over another 


channel in case of interference, is used in order to transmit data, Bluetooth


devices must first stablish a connection. One single device is capable of


connecting to up to 7 devices and communicating with each one of them 


simultaneously.This is done by using a connection model known 


as“master-slave”, in which the device that initiates the connection takes the  


role of master over the other devices. Whenever a master and a slave 


establish a connection, a bond is created, enabling them to transmit and


receive data.


Designed as a low-power technology, Bluetooth is meant to function on battery 


power devices over relatively short distances. Just as with Wi-Fi, the maximum 


distance over which a Bluetooth device can stablish a connection depends on


its output power, as well as other factors such as signal reflection caused by 


obstacles.Three different classes are used to classify Bluetooth devices 


according to their maximum output power and their corresponding maximum 


range. These can be seen in Table as below:



Maximum Output Power



20 db

Up to 100m


4 db

Up to 10m


0 db