BLE

Bluetooth Low Energy (BLE) is a wireless personal area network technology designed for low power consumption and low cost. It is part of the Bluetooth core specification, introduced with Bluetooth 4.0 in 2010. BLE operates in the 2.4 GHz ISM band and uses frequency hopping to minimize interference while transmitting small packets. It is optimized for devices that require long battery life and can transmit data infrequently, such as sensors, beacons, and wearable devices.

BLE communications use advertising, scanning, and optional connections. Data is exchanged with the Generic Attribute Profile (GATT) over the ATT protocol, organized into services and characteristics. Roles include peripheral devices that advertise and connect to central devices, which scan and initiate connections. Connection parameters (interval, latency, and timeout) govern power use and responsiveness. BLE uses three advertising channels (37, 38, and 39) and supports encryption and LE Secure Connections for security.

Since its introduction, subsequent Bluetooth releases have increased data rate and features. Bluetooth 4.2 added higher throughput and privacy improvements; Bluetooth 5 introduced up to 2 Mbps and longer range; Bluetooth 5.1 added direction finding, and Bluetooth 5.2 introduced Isochronous Channels for LE Audio.

Applications include proximity beacons, health and fitness sensors, smart home devices, and asset tracking. Limitations include modest data throughput and variable range depending on environment, as well as interoperability considerations with older devices. The BLE specification is maintained by the Bluetooth Special Interest Group (SIG) and is widely supported across mobile and embedded platforms.