Bluetooth in IoT

Introduction

Bluetooth wireless technology is a short range communications technology.
Intended for replacing cables connecting portable units.
Maintains high levels of security.
Bluetooth technology is based on Ad-hoc technology also known as Ad-hoc Piconets.

Features

Bluetooth technology operates in the unlicensed industrial, scientific and medical (ISM) band at 2.4 to 2.485 GHZ.
Uses spread spectrum hopping, full-duplex signal at a nominal rate of 1600 hops/sec.
Bluetooth supports 1 Mbps data rate for version 1.2 and 3Mbps data rate for Version 2.0 combined with Error Data Rate.
Bluetooth operating range depends on the device:

         - Class 3 radios have a range of up to 1 meter or 3 feet
         - Class 2 radios are most commonly found in mobile devices have a range of 10 meters or 30 feet
         - Class 1 radios are used primarily in industrial use cases have a range of 100 meters or 300 feet.

Connection Establishment

Inquiry run by one Bluetooth device to try to discover other devices near it.

Process of forming a connection between two Bluetooth devices.

A device either actively participates in the network or enters a low-power sleep mode.

Modes

Protocol Stack

Baseband

Physical layer of the Bluetooth.
Manages physical channels and links.
Other services include:
   - Error correction
   - Data whitening
   - Hop selection
   - Bluetooth security
Manages asynchronous and synchronous links.
Handles packets, paging and inquiry.