BLUETOOTH

Bluetooth

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1. Overview

The original bluetooth is known as Bluetooth Classic and was designed as a short-range wireless point-to-point communications protocol.

Personal area network (PAN) was called a piconet. 1 central device and up to 7 peripherals.

The bluetooth logo is shown below:

bluetooth 4 0 icon
Figure 1. The Bluetooth icon/logo.

3. Advanced Audio Distribution Profile (A2DP)

This is a bluetooth standard which supports the streaming of audio between bluetooth-enabled devices.

4. Bluetooth 4.0

In 2010, the Bluetooth Core Specification version 4.0 was released. This included Bluetooth Low Energy (BLE), which is now more commonly known as Bluetooth Smart. Bluetooth Smart specifies a hub-and-spoke connection model (with broadcast support), but no mesh topology.

An attribute is a piece of labelled and addressable data. A characteristic is a group of attributes, and a service is a group of attributes.

attribute < characteristic < service

Bluetooth 4.0 uses the server/client paradigm.

5. Bluetooth Smart Mesh Working Group

In 2017, a set of three specifications were released by the Bluetooth SIG:

  • Mesh Profile

  • Mesh Model

  • Mesh Device Properties

These specifications allowed Bluetooth devices to form a mesh network. Mesh Profiles use Bluetooth LE for it’s underlying radio communications, and as such Mesh Profiles work with Bluetooth 4.2 and Bluetooth 5 devices.

Bluetooth Mesh data packets can be up to 384 bytes.

Two types of encryption keys:

  1. Network keys: Specific to a physical network.

  2. Application keys: Specific to the function of the data, e.g. reading sensor values vs. configuring the sensor.

5.1. Generic Models

5.1.1. Generic OnOff Server

5.1.2. Generic Level Server


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