Bluetooth

Bluetooth is a standard for wireless communications based on a radio system designed for short-range connectivity for portable personal devices. It defines a whole communication stack that allows devices to find each other and advertise the services they offer. Bluetooth is extensively used in WPAN technology. IEEE 802.15.1 standard specifies the operation and architecture of Bluetooth devices, but the operation is concerned only for physical layer and medium access control (MAC) layer. The protocol layers and applications are standardized by Bluetooth SIG. The channels are accessed using an FHSS technique, with a signal rate of 1 Mb/s, using Gaussian shaped frequency shift keying (GFSK) modulation.

Bluetooth devices use the 2.4 GHz band, which is licence free Industrial, Scientific and Medical (ISM) frequency band for its radio signals and enables communications to be established between devices up to a maximum distance of around 100 metres. Bluetooth's main strength is its ability to simultaneously handle both data and voice transmissions, allowing such innovative solutions as a mobile hands-free headset for voice calls, print to fax capability, and automatically synchronizing PDA, laptop, and cell phone address book applications.

The two most prevalent implementations of the specification are Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR), which was adopted as version 2.0/2.1, and Bluetooth with low energy (LE), which was adopted as version 4.0/4.1/4.2/5.0. Bluetooth BR/EDR establishes a relatively short-range, continuous wireless connection, with EDR data rate of 2-3 Mbit/s respectively which makes it ideal for use cases such as streaming audio. BLE allows for short bursts of long-range radio connection, making it ideal for Internet of Things applications that don’t require continuous connection but depend on long battery life.