Bluetooth Low Energy ( Bluetooth LE , colloquially BLE , previously marketed as Bluetooth Smart ) is an area network personal wireless technology designed and marketed by the Bluetooth Special Interest Group (Bluetooth SIG) aimed at new applications in the health care, fitness, flare, security, and home entertainment industries. Compared to Bluetooth Classic, Bluetooth Low Energy is intended to provide significantly reduced power consumption and cost while maintaining similar communication coverage.
Mobile operating systems including iOS, Android, Windows Phone and BlackBerry, as well as macOS, Linux, Windows 8 and Windows 10, natively support Bluetooth Low Energy. Bluetooth SIG predicts that by 2018, more than 90 percent of smartphones that support Bluetooth will support Bluetooth Low Energy.
Video Bluetooth Low Energy
Compatibility
Bluetooth Low Energy is not compatible with the previous Basic/Data Improvement (BR/EDR) protocol (commonly called "classic"). The Bluetooth 4.0 specification allows the device to implement one or both LE and BR/EDR systems.
Bluetooth Low Energy uses the same 2.4 GHz radio frequency as the classic Bluetooth, which allows dual-mode devices to share a single radio antenna. However, LE uses a simpler modulation system.
Maps Bluetooth Low Energy
Branding
In 2011, Bluetooth SIG announced the Bluetooth Smart logo to clarify the compatibility between new low energy devices and other Bluetooth devices.
- Bluetooth Smart Ready shows a dual mode device compatible with Classic and low-energy peripherals.
- Bluetooth Smart demonstrates low-energy devices that require Smart Ready or other Smart devices to work.
With SIG May 2016 branding information Bluetooth, Bluetooth SIG began to gradually release the Bluetooth Smart logo and Bluetooth Smart Ready and word marks and have re-used the Bluetooth logo and word mark. The logo uses a new blue color.
Target market
Bluetooth SIG identifies a number of markets for low-energy technologies, particularly in the smart home, health, sports, and fitness sectors. The quoted profits include:
- low power requirements, operating for "month or year" on the button cell
- small size and low cost
- compatibility with a mobile phone base, tablet and a built-in computer
History
In 2001, researchers at Nokia determined various scenarios not covered by contemporary wireless technology. The company began developing wireless technologies adapted from Bluetooth standards that will provide lower power and cost usage while minimizing the difference from Bluetooth technology. The results were published in 2004 using the name Bluetooth Low End Extension.
After further development with partners especially Logitech and in the European project MIMOSA, is actively promoted and supported also by STMicroelectronics from an early stage, the technology was released to the public in October 2006 under the brand name Wibree. After negotiations with the Bluetooth SIG members, an agreement was reached in June 2007 to include Wibree in future Bluetooth specifications as an ultra low-power Bluetooth technology.
The technology is marketed as Bluetooth Smart and integration to version 4.0 of the Core Specification completed in early 2010. The first smartphone to implement the 4.0 specification is the iPhone 4S, released in October 2011. A number of other manufacturers are releasing Bluetooth Low Energy Ready devices in 2012.
Bluetooth SIG officially launched Bluetooth 5 on June 16, 2016 during a media event in London. One of the changes on the marketing side is that they drop the number of points, so now it's just called Bluetooth 5 (and not Bluetooth 5.0 or 5.0 LE as for Bluetooth 4.0). This decision was made allegedly to "simplify marketing, and communicate user benefits more effectively". On the technical side, Bluetooth 5 will double the range by using increased transmit power or a coded physical layer, doubling the speed by using an optional half-time symbol compared to Bluetooth 4.x, and delivering an eightfold increase in data broadcast capacity by increasing the transmission ad's data length Bluetooth energy is low compared to Bluetooth 4.x, which can be important for IoT applications where nodes are connected throughout the home.
Bluetooth SIG released Mesh Profile and Mesh Model specifications officially on July 18, 2017. The Mesh specification allows the use of Bluetooth Low Energy for many-to-many communications devices for home automation, sensor networks, and other applications.
Apps
Borrowing from the original Bluetooth specification, Bluetooth SIG defines several profiles - specifications of how the device works in a particular application - for low-energy devices. Manufacturers are expected to apply the appropriate specifications for their devices to ensure compatibility. The device can load various profile implementations.
Most current low energy application profiles are based on generic attribute profiles (GATT), a general specification for sending and receiving short data chunks known as attributes via low energy links. The Bluetooth mesh profile is an exception to this rule because it is based on a Public Access Profile (GAP).
mesh profile
The Bluetooth mesh profile uses Bluetooth Low Energy to communicate with other Low Energy Bluetooth devices in the network. Each device can forward this information to other Bluetooth Low Energy devices that create a "mesh" effect. For example, turn off all building lights from one smartphone.
- MESH (Mesh Profile) - for basic mesh networks.
- MMDL (Mesh model) - for application layer definitions. The term "model" is used in the mesh specification instead of "profile" to avoid ambiguity.
Health care profile
There are many profiles for Bluetooth Low Energy devices in health care applications. The Continua Health Alliance consortium promotes this in collaboration with Bluetooth SIG.
- BLP (Blood Pressure Profile) - for blood pressure measurement.
- HTP (Health Thermometer Profile) - for medical temperature measurement devices.
- GLP (Glucose Profile) - to monitor blood glucose.
- CGMP (Profile of Continuous Glucose Monitor)
Sports and fitness profile
Profiles for sport and fitness accessories include:
- BCS (Body Composition Service)
- CSCP (Cycling Speed ​​and Cadence Profile) - for sensors attached to a bicycle or exercise bike to measure rhythm and wheel speed.
- CPP (Power Profile Cycling)
- HRP (Heartbeat Profile) - for devices that measure heart rate
- LNP (Location and Navigation Profile)
- RSCP (Running Speed ​​and Cadence Profiles)
- WSP (Scale Weight Profile)
Internet Connectivity
- IPSP (Internet Protocol Support Profile)
Generic Sensors
- ESP (Environmental Sensing Profile)
- UDS (User Data Service)
HID Connectivity
- HOGP (HID over GATT Profile) allows Bluetooth-enabled mouse, keyboard, and Bluetooth-enabled wireless devices to offer long-life battery life.
Proximity sensing
The "electronic leash" app is perfect for long battery life for 'always on' devices. The iBeacon device manufacturers apply the appropriate specifications for their devices to take advantage of remote sensing capabilities supported by Apple's iOS device.
Relevant app profiles include:
- FMP - the "find me" profile - allows one device to issue a warning on the wrong second device.
- PXP - proximity profile - allows the proximity monitor to detect whether the proximity reporter is in close proximity. Physical proximity can be estimated using the radio receiver's RSSI value, although this does not have an absolute distance calibration. Typically, an alarm may sound when the distance between devices exceeds a set threshold.
Warning and timing profile
- Your phone alert status profile and alert notification profile allow client devices to receive notifications like incoming call notifications from other devices.
- The time profile allows the current time and time zone information on the client device to be set from the server device, such as between watches and mobile network time.
Battery
- The Battery Service exposes Battery Level and Battery Level from one battery or a set of batteries in the device.
Implementation
Chip
Beginning in late 2009, the implementation of Bluetooth Low Integrated integrated circuit was announced by a number of manufacturers. Implementations generally use software radios so updates to specifications can be accommodated through firmware upgrades.
Hardware
Mobile devices are currently released with support for hardware and software for classic Bluetooth and Bluetooth Low Energy.
Operating system
- iOS 5 and later
- Windows Phone 8.1
- Windows 8 and later
- Android 4.3 and later
- BlackBerry 10
- Linux 3.4 and later via BlueZ 5.0
- Together OS 5.2
Technical details
Radio interface
Bluetooth Low Energy technology operates within the same spectrum range (2,400-2,4835 GHz ISM band) as a classic Bluetooth technology, but uses different channel sets. Instead of the classic 79 1-MHz Bluetooth channel, Bluetooth Low Energy has 40 2-MHz channels. In the channel, data is transmitted using Gaussian frequency shift modulation, similar to the classic Bluetooth Basic Tariff scheme. The bit rate is 1 Mbit/s (with 2 Mbit/d option in Bluetooth 5), and the maximum transmit power is 10 mW (100 mW in Bluetooth 5). Further details are given in Volume 6 of Part A (Physical Layer Specification) of the Main Specifications of Bluetooth V4.0.
Bluetooth Low Energy uses frequency hopping to troubleshoot narrowband problems. Classic Bluetooth also uses frequency hopping but the details are different; as a result, while the FCC and ETSI classify Bluetooth technology as the FHSS scheme, Bluetooth Low Energy is classified as a system that uses digital modulation techniques or direct sequential distributive spectrum.
More technical details can be obtained from official specifications as published by Bluetooth SIG. Note that power consumption is not part of the Bluetooth specification.
Ads and inventions
The BLE device is detected through a procedure based on the broadcast ad package. This is done using 3 separate channels (frequency), to reduce interference. Advertising devices deliver packages on at least one of these three channels, with repetition periods called ad intervals. To reduce the likelihood of multiple consecutive collisions, a random delay of up to 10 milliseconds is added to each ad interval. The scanner listens for a channel for the duration called scanning window, which is periodically repeated every scan interval.
The discovery of latency is therefore determined by a probabilistic process and depends on three parameters (ie, advertising interval, scan interval and window scanning). The BLE discovery scheme adopts a periodic interval-based technique, in which the upper limit of the latency discovery can be inferred for some parametrizations. While the latency of the BLE invention can be approximated by a model for protocols based on pure periodic intervals, random delays added to each advertising interval and the discovery of three channels may lead to deviations from these predictions, or potentially causing unlimited latency for certain parametrizations.
Software model
All Bluetooth Low Energy devices use Generic Attribute Profile (GATT). The application programming interface offered by the conscious Bluetooth Low Energy operating system will usually be based on GATT concepts. GATT has the following terminology:
- Client
- Devices that initiate GATT commands and requests, and receive responses, for example, a computer or smartphone.
- Server
- Devices that receive GATT commands and requests, and return a response, for example, a temperature sensor.
- Characteristics
- The value of data transferred between the client and server, for example, the current battery voltage.
- Services
- A set of related characteristics, which operate together to perform certain functions. For example, the Health Thermometer service includes characteristics for temperature measurement values, and time intervals between measurements.
- Descriptor
- The descriptor provides additional information about a characteristic. For example, the temperature value characteristics may have an indication of the unit (eg Celsius), and the maximum and minimum values ​​that can be measured by the sensor. Descriptors are optional - each characteristic can have any number of descriptors.
Some services and characteristic values ​​are used for administrative purposes - for example, model names and serial numbers can be read as standard characteristics in the Generic Access service. The Service may also include other services as subfunctions; the main function of the device is called the main service , and the auxiliary function they mean is secondary services .
Identifier
Services, characteristics, and descriptors are collectively referred to as attributes , and identified by UUIDs. Each implementer may choose a random or pseudorandom UUID for exclusive use, but the Bluetooth SIG has ordered various UUIDs (from the form GATT operation
The GATT protocol provides a number of commands for clients to find information about the server. These include:
- Find the UUID for all major services
- Find services with given UUID
- Find secondary services for certain key services
- Find all the characteristics for a particular service
- Find characteristics that match the specified UUID
- Read all descriptors for certain characteristics
Commands are also provided for reading (transferring data from server to client) and writing (from client to server) characteristic values:
- The value can be read either by specifying the character UUID, or by the handle value (returned by the information discovery command above).
- The write operation always identifies characteristics with the handle, but has the choice of whether a response from the server is required or not.
- The operation 'Length of reading' and 'Write length' can be used when the characteristic data length exceeds the radio connection MTU.
Finally, GATT offers notifications and indications . The client may request notice for certain characteristics of the server. The server can then send value to the client whenever it is available. For example, a temperature sensor server can notify its clients whenever it takes measurement. This avoids the client's need for a server poll, which will require the server's radio circuitry to continue operating.
The indication is similar to a notification, except that it requires a response from the client, as a confirmation that it has received the message.
Battery effect
Bluetooth Low Energy is designed to enable devices with low power consumption. Several chip manufacturers including Cambridge Silicon Radio, Dialog Semiconductor, Nordic Semiconductor, STMicroelectronics, Cypress Semiconductor, Silicon Labs, and Texas Instruments have introduced their Bluetooth Low Energy chipsets that have been optimized for the past few years. Devices with peripheral and central roles have different power requirements. A study by the flare software company, Aislelabs, reported that peripherals, such as proximity beacons, typically function for 1-2 years with a 1,000mAh coin cell battery. This is possible because of the power efficiency of the Bluetooth Low Energy protocol that transmits only small packets when compared to the Bluetooth Classic which is also suitable for audio data and high bandwidth.
Conversely, continuous scanning for the same beacon in a central role can consume 1,000 mAh in a few hours. Android and iOS devices also have very different battery impacts depending on the type of scan and the number of Bluetooth devices surrounding Low Energy. With newer chipsets and advances in software, both Android and iOS phones now have a negligible power consumption in the real-life Bluetooth Energy usage scenario.
See also
- ANT
- ANT
- DASH7
- Eddystone
- IEEE 802.15/IEEE 802.15.4-2006
- Indoor positioning system (IPS)
- MyriaNed
- Ultra-wide band (UWB)
- UWB Forum
- WiMedia Alliance
- WirelessHD
- Wireless USB
- Zigbee
- Z-Wave
Note
References
Further reading
- "Specifications - Bluetooth Technology Web Site". www.bluetooth.org . Ã, " Bluetooth 4.0 Core Specification "- GATT is described in full at Volume 3, Part G
External links
- Official website
-
Gomez, Carles; Oller, Joaquim; Paradells, Josep (August 29, 2012). "Overview and Evaluation of Low-Energy Bluetooth: An Increased Low-Power Wireless Technology". Sensor . 12 (12): 11734-11753. doi: 10.3390/s120911734. ISSN 1424-8220.
Source of the article : Wikipedia
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