Bluetooth Smart (Low Energy) Technology
Bluetooth SIG announced the formal adoption of Bluetooth® Core Specification version 4.0, it included the hallmark Bluetooth Smart (low energy) feature. This final step in the adoption process opened the door for qualification of all Bluetooth product types to version 4.0 and higher.
Bluetooth Smart (low energy) wireless technology features:
- Ultra-low peak, average and idle mode power consumption
- Ability to run for years on standard coin-cell batteries
- Low cost
- Multi-vendor interoperability
- Enhanced range
Bluetooth Smart (low energy) technology allows enhancement of devices like watches, toothbrushes or toys with Bluetooth wireless technology. It also provides the ability for developers to incorporate new functionalities into devices already enabled by Bluetooth technology such as sports & fitness, health care, human interface (HIDs) and entertainment devices. For example, sensors in pedometers and glucose monitors will only run low energy technology. These single mode devices benefit from the power savings provided by v4.0 as well as the low cost implementation. Watches take advantage of both low energy technology while collecting data from body-worn fitness sensors and Classic Bluetooth technology when sending that information to a PC, or displaying caller ID information when wirelessly connected to a smartphone. Smartphones and PCs, which support the widest range of use cases for the specification, utilizing the full dual-mode package with Classic, low energy and high speed versions of the technology running side by side.
Generic Attribute Profile
The latest Bluetooth specification uses a service-based architecture based on the attribute protocol (ATT). All communication in low energy takes place over the Generic Attribute Profile (GATT). An application or another profile uses the GATT profile so a client and server can interact in a structured way.
The server contains a number of attributes, and the GATT Profile defines how to use the Attribute Protocol to discover, read, write and obtain indications. These features support a service-based architecture. The services are used as defined in the profile specifications. GATT enables you to expose service and characteristics defined in the profile specification.
The GATT profile is also part of the core and defined in the core specification.
The first specification of Bluetooth low energy wireless technology included two profiles to optimize its functionality for a specific group of products: remote display profile and a sensor profile.
Below you can find links to the specification to current list of profiles
Adopted GATT based Bluetooth Profiles and Services
The GATT architecture makes it easy to both create and implement new profiles. Many new profiles are under development so this continues to grow. The simplicity of implementing the profiles contributes to a rapid growth of applications and embedded devices supporting these.
|GATT-Based Specifications (Qualifiable)||Adopted Versions|
|ANP||Alert Notification Profile||
|ANS||Alert Notification Service||
|CTS||Current Time Service||
|DIS||Device Information Service||
|FMP||Find Me Profile||
|HTP||Health Thermometer Profile||
|HTS||Health Thermometer Service||
|HRP||Heart Rate Profile||
|HRS||Heart Rate Service||
|IAS||Immediate Alert Service||
|LLS||Link Loss Service||
|NDCS||Next DST Change Service||
|PASP||Phone Alert Status Profile||
|PASS||Phone Alert Status Service||
|RTUS||Reference Time Update Service||
|TPS||Tx Power Service||
Link layer specification
The link layer provides low power idle mode operation, simple device discovery and reliable point-to-multipoint data transfer with advanced power-save and encryption functionalities.
Single mode and dual mode
Bluetooth Smart (low energy) wireless technology contains two equally important implementation alternatives: single mode and dual mode. Small devices like watches and sports sensors use the single mode Bluetooth Smart (low energy) implementation. Dual mode implementations use parts of the Bluetooth hardware, sharing one physical radio and antenna.
While connecting to a single mode Bluetooth Smart (low energy) device (without utilization of classic Bluetooth wireless technology) the device enjoys advantages of low-power consumption. However, these details are not evident to the end user—when using a device (either single mode or dual mode) the end user will not be aware if the device is using classic Bluetooth wireless technology, or the Bluetooth Smart (low energy).