Bluetooth Low Energy
During 2011, Bluetooth v4.0 with the hallmark feature low energy technology entered the market. u-blox Bluetooth low energy modules are especially well suited for sensors, actuators and other small devices in the "Internet of Things" (IoT) that require internet connectivity and extremely low power consumption. Bluetooth low energy is also referred to as "Bluetooth smart" when used in single-mode. When a device possesses both Classic Bluetooth and Bluetooth low energy modes, it is referred to as "Bluetooth Smart Ready".
Low Energy Bluetooth was designed for devices that do not stream data continuously but instead transfer small packets of data as needed. Similar to Classic Bluetooth it operates in the 2.4 GHz ISM band using frequency hopping. The use cases with the transmitter spend less time on the air and need less energy when on the air. This plus the fact that Bluetooth low energy devices can make connections very quickly (in just a few msec) is the key to low power consumption.
Typical Bluetooth low energy devices are sensors like room temperature, battery level, patient monitoring sensors etc.