Bluetooth / 802.15.1
Bluetooth is an open wireless protocol for data exchange according IEEE 802.15.1 within short ranges creating Personal Area Networks (PAN). Fixed and mobile devices can include this technology. Primarily it is designed for short range and low-power consumption, with a focus on application such as
- Mobile phones, laptops, personal computers
- Printers, digital cameras and other peripherals
- GPS systems
- Medical devices
- Consumer Devices
- Industrial automation, sensor system
Bluetooth provides a way to connect and exchange information between devices through a secure connection in the globally unlicensed ISM 2.4 GHz short-range radio frequency band. In a piconet, which is an adhoc network, a Bluetooth master can communicate with up to 7 devices. If two or more piconets are connected to each other, this is called scatternet. The range is dependent on the power class and the data rate is mainly dependent on the used protocol stack version.
On top of the complex stack (incl. e.g. HCI, LMP, L2CAP, SDP) various profiles for different applications are used. The different profiles are describing specific application in order to provide full compatibility between the devices.
Main profiles are e.g. Serial Port Profile (SPP), Health Device Profile (HDP), Headset Profile (HSP) and more.
Bluetooth Version 4.0 also called Low Energy or officially marked Bluetooth SMART is not backwards compatible to Bluetooth v3.0 and V2.x. It is made for low power consumption using different hardware, frequency hopping and the Low Power Stack is different structured and less complex.
Also profiles are different in Bluetooth V4.0 and actually very limited regarding functionality, because these are written to support sensors and actors mainly. Hence no longer complete device are described in profiles, but more single functions and simple services.