What is BLE? -Bluetooth Low Energy basics
There are various wireless technologies developed for short range applications such as voice, data, audio and video. Bluetooth and Bluetooth Low Energy are among them.
Traditional bluetooth is connection oriented. When a device is connected, a link is maintained, even if there is no data flowing. Here sniff modes allow devices to sleep which reduces power consumption and hence provides months of battery life. Peak transmit current is typically around 25 mA. Even though bluetooth has been independently shown to be lower power compare to other radio standards; it is still not low enough power for the coin cells and energy harvesting applications.
Hence BLE(Bluetooth Low Energy) technology is developed for these low power applications. It is one of the technologies used in IoT(Internet of Things). In IoT, things have data which is needed by Web Services. Bluetooth low energy provides the technology to connect these two. It uses asynchronous connectionless MAC which helps to achieve low latency and fast transactions (e.g. 3ms from start to finish). BLE uses new PHY, new radio and new protocol stack compare to generic bluetooth.
Following are the features of BLE referred as Bluetooth Low Energy:
|specification/feature||BLE(Bluetooth Low Energy) support|
|Range||Typically 5-10 m, 150 meters can be achieved in open field (implementation specific)|
|Output power||10 mW (10dBm)|
|Max. current||15mA (implementation specific)|
|Data rate(Throughput)||1 Mbps (But it is not optimized for file transfer application)|
|connections||> 2 billion|
|Modulation||GFSK at 2.4 GHz|
|Robustness||Adaptive frequency hopping, 24 bit CRC|
|Security||128 bit AES CCM|
|Sleep current||Approx. 1 µA (Implementation specific)|
|Modes||broadcast, connection, event data models, reads, writes|
|RF Band||2400 MHz|
|Spreading||FHSS (2 MHz channel BW)|
Above figure-1 depicts BLE network topologies. Refer BLE tutorial➤ which describes BLE technology features, BLE(Bluetooth Low Energy) network, BLE channels, BLE messages, BLE protocol stack, BLE Applications (BLE Apps) etc.
Refer difference between bluetooth and Bluetooth Low Energy which compares both and provides the similarities and difference between these technologies.