Low power bluetooth

On June 12, 2007, Bluetooth SIG announced that Wibree would become part of the Bluetooth specification as Ultra Low Energy Bluetooth ( ULP Bluetooth ) technology . The result should be wireless technology with low power consumption and significantly increased battery life, comparable to those of circuits using ZigBee .

On April 20, 2009, Bluetooth SIG introduced the new low-power Bluetooth technology as an optional stack protocol, fully compatible with other existing Bluetooth protocol stacks. Previous names such as Wibree and ULP Bluetooth (Ultra Low Power) have been replaced by the accepted name Bluetooth technology low energy ( Bluetooth low energy ).

December 17, 2009. Bluetooth SIG has published the adoption of low-power Bluetooth wireless technology as a distinctive feature of the 4.0 core version of the Bluetooth specification ^[3] .

The integration of low-power Bluetooth into the core specification was completed in early 2010. The first device to incorporate this technology was the iPhone 4S, released in October 2011. Other manufacturers introduced Bluetooth Smart Ready devices in 2012.

With less power, Bluetooth low-power technology will offer long-term connectivity and connect small devices like sensors and mobile devices within personal area networks (PANs).

The Bluetooth 4.0 specification (and later) actually defines two wireless technologies: BR / EDR (classic Bluetooth, developing from the first version of the standard) and BLE (Bluetooth Low Energy) ^[4] .

Devices that use BLE can be either dual-mode BR / EDR / BLE (called Bluetooth Smart Ready) compatible with classic Bluetooth devices, or single-mode BLE (Bluetooth Smart) ^{[4] [2]} .

The main units of a Bluetooth device are ^[4] :

• Application ( English application ) - implements the logic of work useful for the end user;
• The host device, the host ( English host ) - provides the upper levels of the Bluetooth protocol stack;
• Controller ( eng. Controller) - deals with the lower levels of Bluetooth.

Commercial products typically use one of the following hardware solutions ^[4] :

• SoC is a single-chip system that combines an application, host and controller. It is applied in compact inexpensive devices, such as sensors;
• A two-chip solution in which the application and host are connected to the controller via UART , USB , SDIO , etc. ^[5] using the HCI protocol. Such a configuration can be used, for example, in mobile devices;
• A two-chip solution in which the application connects to a communication device (host and controller) using a proprietary protocol.

Application level - the highest level of the protocol stack.

The host level contains the following levels ^[6] :

• GAP (Generic Access Profile) - sharing profile,
• GATT (Generic Attribute Profile) - a profile of common attributes,
• L2CAP (Logical Link Control and Adaptation Protocol) - a protocol of logical connection and adaptation,
• ATT (Attribute Protocol) - attribute protocol,
• SM (Security Manager) - Security Manager,
• HCI (Host Controller Interface) - host controller interface, part on the host side,

The host is connected to the controller by the HCI protocol and has levels ^[6] :

• HCI - host controller interface on the controller side,
• LL (Link Layer) - link layer,
• PHY is the physical layer.

See also bluetooth protocol stack .

The Bluetooth standard clearly distinguishes between the concepts of protocol and profile . Protocols are an integral part of the specification and are “horizontal” parts of the individual layers of the Bluetooth stack. Profiles are “vertical” slices of functionality and can be either mandatory ( Generic Access Profile or GAP, Generic Attribute Profile or GATT), or specific to a given device (for example, Find Me Profile , Proximity Profile ). Manufacturers can define their own profiles, for example, Apple Notification Center Service iBeacon and Apple Notification Center Service ^[7] .

Low-power Bluetooth is an extension of the specification of the basic Bluetooth wireless technology, which will add new functionality and allow the creation of applications for remote control, medical surveillance, sports sensors and other devices. Low-power Bluetooth will provide an opportunity to improve existing applications, expanding the applicability and functionality of Bluetooth technology.

Appropriate chips can be integrated into products such as watches, wireless keyboards, gamepads, and body sensors that can connect to host devices, such as mobile phones, personal digital assistants (PDAs), and personal computers (PCs).

Software Updates

Relevant applications for existing devices can be opened to use low-power Bluetooth technology through an update. This will enable existing Bluetooth technology software to receive data from Bluetooth with low power consumption. However, the ability to communicate in duplex mode is limited with certain frequency distribution schemes of traditional Bluetooth technology. Widespread devices such as mobile phones, personal digital assistants ( PDAs ) and personal computers ( PCs ) can receive data transmitted by low-power Bluetooth devices as receiving devices for complex tasks.

Therefore, Bluetooth low-power technology can connect any personal network according to IEEE 802.15 ( WPAN ) which communicates with each simple device with other devices for complex tasks, as well as to support a gateway for transmitting information to other network objects.

Sometimes you can "restore" the scattered radiation energy or energy of motion. Such “garbage-cleaning” systems can power ultra-low-power Bluetooth, which leads to something like dust sensors, very small, independent, affordable network sensors that tell you the whole picture around, they are scattered everywhere and not exhausting energy. They are also reliable.

Standardization

In the market for proprietary communications solutions, low-power Bluetooth technology defines itself as:

• Widespread Industry Standard Protocol (Bluetooth SIG)
• internationally accepted industry standard for transmission (IEEE 802.15.1)
• low price due to chip integration
• compatible with existing Bluetooth devices through updates

Hardware platforms

Several manufacturers are releasing chips for Bluetooth LE peripherals, for example, Nordic Semiconductor with nRF51, nRF52, Texas Instruments series chips with CC2541 on-chip system . In addition, instead of developing their own radio solutions on their own, manufacturers can purchase ready-made modules that have passed the appropriate, fairly expensive certification. At the beginning of 2014, Laird BL600, Bluegiga BLE112 / BLE113, and RFDuino modules (for the Arduino platform) were available ^[9] .

As an example, below are the characteristics of a system based on an nRF51 series crystal ^[9] :

• ARM (architecture) Cortex-M0 clocked at 16 MHz
• From 128 to 256 KB of flash memory , of which about 90 KB takes the Bluetooth LE stack
• 16 KB of SRAM , of which 8 KB can be used by the application, and the rest uses the stack

• Wibree
• ANT +

• Kevin Townsend; Carles Cufí; Akiba; Robert Davidson Getting Started with Bluetooth Low Energy. - O'Reilly Media, Inc., 2014 .-- 180 p. - ISBN 978-1-4919-4951-1 .