Bluetooth low energy (Bluetooth LE, BLE, marketed as Bluetooth Smart) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group aimed at novel applications in the healthcare, fitness, beacons, security, and home entertainment industries. Compared to Classic Bluetooth, Bluetooth Smart is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range.
Bluetooth Smart was originally introduced under the name Wibree by Nokia in 2006. It was merged into the main Bluetooth standard in 2010 with the adoption of the Bluetooth Core Specification Version 4.0.
Mobile operating systems including iOS, Android, Windows Phone and BlackBerry, as well as OS X, Linux, and Windows 8, natively support Bluetooth Smart. The Bluetooth SIG predicts more than 90 percent of Bluetooth-enabled smartphones will support Bluetooth Smart by 2018.
Borrowing from the original Bluetooth specification, the Bluetooth SIG defines several profiles — specifications for how a device works in a particular application — for low energy devices. Manufacturers are expected to implement the appropriate specifications for their device in order to ensure compatibility. A device may contain implementations of multiple profiles.
All current low energy application profiles are based on the generic attribute profile, or GATT, a general specification for sending and receiving short pieces of data known as attributes over a low energy link. Bluetooth 4.0 provides low power consumption with higher bit rates.
In 2014, Cambridge Silicon Radio (CSR) launched CSR Mesh. CSR Mesh protocol uses Bluetooth Smart to communicate with other Bluetooth Smart devices in the network. Each device can pass the information forward to other Bluetooth Smart devices creating a “mesh” effect. For example, switching off an entire building of lights from a single smartphone. The Bluetooth SIG recently formed the Smart Mesh study group to research and define its use cases in an effort to define a standard specification.
Health care profiles
There are many profiles for Bluetooth Smart devices in healthcare applications. The Continua Health Alliance consortium promotes these in cooperation with the Bluetooth SIG.
BLP (Blood Pressure Profile)— for blood pressure measurement.
HTP (Health Thermometer Profile) — for medical temperature measurement devices.
GLP (Glucose Profile) — for blood glucose monitors.
CGMP (Continuous Glucose Monitor Profile)
Sports and fitness profiles
Profiles for sporting and fitness accessories include:
BCS (Body Composition Service)
CSCP — for sensors attached to a bicycle or exercise bike to measure cadence and wheel speed.
CPP (Cycling Power Profile)
HRP (Heart Rate Profile) — for devices which measure heart rate
LNP — location and navigation profile.
RSCP(Running Speed and Cadence Profile)
WSP (Weight Scale Profile)
IPSP (Internet Protocol Support Profile)
ESP (Environmental Sensing Profile)
UDS (User Data Service)
HOGP (HID over GATT Profile)
"Electronic leash" applications are well suited to the long battery life possible for 'always-on' devices. Manufacturers of iBeacon devices implement the appropriate specifications for their device to make use of proximity sensing capabilities supported by Apple Inc. compatible iDevices.
Relevant application profiles include:
FMP — the "find me" profile — allows one device to issue an alert on a second misplaced device.
PXP — the proximity profile — allows a proximity monitor to detect whether a proximity reporter is within a close range. Physical proximity can be estimated using the radio receiver's RSSI value, although this does not have absolute calibration of distances. Typically, an alarm may be sounded when the distance between the devices exceeds a set threshold.
Alerts and time profiles
The phone alert status profile and alert notification profile allow a client device to receive notifications such as incoming call alerts from another device.
The time profile allows current time and time zone information on a client device to be set from a server device, such as between a wristwatch and a mobile phone's network time.