It is a Wireless technology standard for exchanging data over short distances. It uses UHF radio waves in the ISM band from 2.4 to 2.485 GHz

Who invented Bluetooth?

Dr. Jaap Haartsen, who invented Bluetooth while working at Ericsson in the 1990s, has been nominated as a finalist by the European Patent Office in the industry category for its European Inventor Award

How does it works?

A Bluetooth® device uses radio waves instead of wires or cables to connect to a phone or computer. A Bluetooth product, like a headset or watch, contains a tiny computer chip with a Bluetooth radio and software that makes it easy to connect. When two Bluetooth devices want to talk to each other, they need to pair.

Usage of Bluetooth

How far can Bluetooth connect?

Generally there are three classes

  • Class 1 – Most powerful, can operate up to 100m
  • Class 2 – Most common range, can operate up to 10m
  • Class 3 - Least powerful and don’t go much beyond 1m

Version comparison


Introduced in 1998 and this version is no longer used. There were lot of issues with this version.

1.1 and 1.2

Noise was increased and transmission speed increased (721 kbps) and network implementation was anonymous. This version allows you to send longer voice messages, and use stereo audio transmission.

2.0 and 2.1

Update 2.0 was released in 2004, 2.1 in 2007. The difference between them lies in the greater energy efficiencies of the latest version. The main feature of Bluetooth 2.0 – the introduction of EDR technology, the speed increases to a theoretical 3 mbps (in practice it was more like 1.5-2 mbps)


Bluetooth 3.0 was published in 2009 and pioneered the use of high-speed data broadcasting. Its speed increased to 24 mbps. The speed increase was due to the installation of two modules: Bluetooth 2.1 + EDR module as well as the wifi 802.11 module.

4.0 And 4.1

Update 4.0 was released in 2010. It fixed the main drawbacks of high speed – excessive energy consumption. Connectivity time was reduced to 5 ms, and the transmission distance increased to 100m.

Update 4.1 was introduced in 2013. Its major improvements relate to the joint operation of Bluetooth and the LTE-standard. Data packets are automatically coordinated to not interfere with each other.


Bluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols. Mandatory protocols for all Bluetooth stacks are: LMP, L2CAP and SDP.


The Link Management Protocol (LMP) is used for set-up and control of the radio link between two devices.


The Logical Link Control and Adaptation Protocol (L2CAP) Used to multiplex multiple logical connections between two devices using different higher level protocols. Provides segmentation and reassembly of on-air packets.


The Service Discovery Protocol (SDP) allows a device to discover services offered by other devices, and their associated parameters.

Error correction and Security

Error correction

FEC (Forward error correction) FEC is a protocol that enables a receiver to not only detect but also correct errors in a transmission

ARQ (automatic repeat request)

Automatic repeat request (ARQ) is a protocol for error control in data transmission. When the receiver detects an error in a packet, it automatically requests the transmitter to resend the packet.


Bluetooth has three security modes:

  • Mode 1 - is no security at all. In this mode the device accepts any connections that are offered to it.

  • Mode 2 - delegates the security to the application. The connection is made and then the application software decides what to do with it.

  • Mode 3 - is the built-in security offered by Bluetooth. In this mode a device can’t even connectunless it obtains permission. A link key or PIN code is used to authenticate the identity of another device.

BT vs other wireless technologies

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Advantages and Disadvantages


  • Eliminate wires
  • Facilitate to date and voice communication
  • Offers formation of Ad hoc networks
  • Free of charge
  • Easy to use


  • Relatively short range
  • Less secure
  • Interference with other devices
  • Lower bandwidth

Latest version of Bluetooth

The latest version is BT 5.0 and it came out in 2017. Bluetooth 5 is faster than 4.0

Future of the Bluetooth

  • BT has good future because it meets a basic need of connectivity
  • Currently protocol is being researched that would support large Ad Hoc networks
  • Improving its security and capabilities
  • New version will meet high speed and large range
  • Many companies are designing impressive Bluetooth applications


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