LowPowerBluetooth

LowPowerBluetooth, commonly called Bluetooth Low Energy (BLE), is a subset of the Bluetooth standard focused on ultra low power operation. Introduced with Bluetooth 4.0 and now part of the Bluetooth Core Specification, BLE is designed for devices that transmit small amounts of data infrequently or must run on small batteries for years. It differs from classic Bluetooth by prioritizing short radio activity, duty cycling, and simplified connection management to minimize energy use.

Its protocol stack centers on two key roles: advertising and connection. A device can broadcast advertisements to announce its presence, while others scan to discover devices. When connection is established, data is exchanged using the GATT (Generic Attribute) profile over a BLE link with configurable connection intervals and slave latency. Shortened radio activity, including wake times and payload sizes, is essential for low power. Connection parameters can be tuned to balance responsiveness and energy efficiency, with typical values spanning from tens of milliseconds to several hundred milliseconds, and long sleep periods in between transmissions.

Power consumption depends on how aggressively the radio is used. In deep sleep with advertisements infrequent, current is in the microampere range; active transmissions raise current to milliamperes briefly. This makes BLE suitable for wearables, beacons, environmental sensors, and IoT devices that require long battery life. BLE is widely supported by smartphones and microcontrollers, and it supports security features such as LE Secure Connections for pairing and encryption. Bluetooth SIG maintains the standard and defines profiles and services such as the Battery Service or Heart Rate Service.

Since Bluetooth 5, BLE gained longer range, higher data rates, and expanded advertising capabilities, improving applicability to more complex IoT scenarios while preserving low power.