Bluetooth Low Energy or Bluetooth LE is a connectivity technology that enables wireless personal area networks using radio waves in the 2.4 GHz band. It consumes minimal energy and is designed to connect devices in a short-range. This article explains the working of Bluetooth LE, its architecture, and its top applications in 2022.
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Bluetooth Low Energy or Bluetooth LE is defined as connectivity technology that enables wireless personal area networks using radio waves in the 2.4 GHz band, which consumes minimal energy and is designed to connect devices across a short-range.Â
Bluetooth was invented in 1998 by the Bluetooth Special Interest Group and has changed how information transmission works in a Personal Area Network (PAN) since. It is a wireless technology standard designed for short-range use, built to facilitate data transfer between devices over a short distance. It creates a PAN and provides an alternative for peripheral connections other than the traditional cables.Â
In itself, Bluetooth has proven to be a beneficial technology. It is found on various devices and is quite popular for file sharing and playing music through speakers and headphones.Â
Bluetooth promises to be an integral technology in the Internet of Things with this preset structure. The problem, however, remains the high amount of energy required to maintain a long-lasting Bluetooth connection. While this is a manageable problem for rechargeable smartphones with large battery capacities, it is pretty problematic for devices with limited power reserves, like devices belonging to the Internet of Things.
This created the need for developing Bluetooth Low Energy (BLE). It accomplishes the primary purpose of Bluetooth technology while maintaining low power consumption.
Bluetooth Low Energy is based on classic Bluetooth technology and provides several of the original features Bluetooth offers while maintaining low power consumption. This cutting down on power makes Bluetooth LE have a shorter range of functionality and is difficult to use when sending large files. Nonetheless, Bluetooth LE is perfect for sending and receiving small amounts of data across a personal area network, which, unlike a local area network (LAN), covers a small area. This has made it a perfect solution for several small devices in the IoT industry.Â
They can communicate with each other, sending and receiving information while retaining their compact design, cost-effectiveness, and battery longevity due to the low power consumption technology of Bluetooth LE.Â
Bluetooth LE was initially referred to as Bluetooth Smart and was first integrated in 2010 in Bluetooth version 4.0. By June 2016, Bluetooth SIG unveiled Bluetooth Low Energy as Bluetooth 5. Since then, it has become quite popular as it has found applications in several industries like manufacturing and commercial technological all-inclusive.Â
Bluetooth Low Energy is currently used in various fields, particularly in the Internet of Things and business advertising industry. The fundamental technology and principle it operates on are adequately suited for these use cases. One real problem Bluetooth LE solves by its technology is favoring low power use. It does this at the risk of expending energy in sustaining continuous data transfer as in classic Bluetooth.Â
Bluetooth LE (also known as Bluetooth Smart) uses the same wireless hopping technology classic Bluetooth uses. It transmits data and connects to various electronic devices via the 2.4 GHz unlicensed radio band. It was, however, designed to be slower, sending a maximum of about 1Mbps as opposed to the faster Bluetooth classic. Bluetooth LE slows data transmission, thus making it consume as little power as 0.01 to 0.5 Watts making it perfect for devices with longer lifespans that only need to share minute amounts of data at intervals.
Besides reducing transmission speed, Bluetooth LE was also designed to conserve power through other techniques. When two devices are connected using the Bluetooth Low Energy network, they communicate for only a few seconds. More so, BLE-enabled devices sleep off or shut down activity between each connection. Rather than prolonged communication lasting for hours, BLE devices can communicate and transmit data effectively, when necessary, and use less energy.Â
These are the core differences between the classic Bluetooth from Bluetooth LE. However, in terms of radio wavebands, they function similarly to share data between devices. Therefore, BLE devices can remain functioning on just one battery for more than a year, which is ideal for Internet of Things implementations.Â
To fully understand how Bluetooth Low Energy works, you must also understand how BLE devices communicate. Communication between BLE devices can occur in two different ways. It can be connection-oriented or based on broadcasting.Â
In the connection-oriented form, a Bluetooth Low Energy device can behave as a central or peripheral device. A BLE device that takes up the role of the primary device in a computer network acts as the client and is responsible for searching for other devices that it can connect to. If it finds such, it then sends out a request for connection and data transmission.Â
That same Bluetooth Low Energy device can also act as a peripheral device or server. In this case, it receives a request for pairing after being found on the radar of a central device. The entire communication process takes four steps â€“ advertise, initiate, connect, and exchange.
The peripheral device sends out timed advertising packets. The central device scans for and uses the advertising packets to find the peripheral device. The initiation stage immediately follows this advertising stage. The primary device initiates a connection request, thus establishing a connection.Â
The last step is when the actual data transmission occurs, and data transmission can be bidirectional.
The other form of communication among Bluetooth Low Energy devices is called broadcasting or, sometimes, bluecasting. This communication does not require a connection to function. A BLE device simply broadcasts raw data in a unidirectional format. This means that data only leaves from one end and is received by any device around the broadcaster that can sense the data.Â
This method of communication does not provide data security to shared documents as anyone, and any device can access shared data without control. However, it does have its own applications where the security of such shared information is not a concern.
Bluetooth Low Energy architecture is also described as the Bluetooth LE protocol stack. It describes the different parts of the Bluetooth LE system, their components, and how they interact to yield expected results. The BLE protocol stack architecture comprises three parts â€“ the application layer, the host layer, and the controller layer.Â
1. The application layer
The application layer of the Bluetooth Low Energy stack architecture is the part that interacts directly with the user. It contains the user interface, application logic, and general application architecture. Underneath this layer is the actual hardware, made of the host and controller layers.Â
2. The host layer
The host layer follows the application layer. It consists of various structures;
- Generic Access Profile (GAP): The GAP is a part of BLE architecture that describes how BLE devices communicate with each other. It includes peripheral or broadcaster devices, advertising information packets, and central device scanning for connection-ready devices.Â
- Generic Attribute Profile (GATT): This operates similarly to the GAP. It describes how attributes are formatted, packaged, and transferred across connected devices following a set of rules. The devices communicate as a client or a server. The client sends requests to the GATT server, which stores the attributes and makes them available on request. The client can either READ or WRITE or perform both functions on the attribute (data).
- Attribute Protocol: The attribute protocol lays the foundation for the GATT profile to function. It is a set of rules guiding how data is accessed. It defines the GATT protocolâ€™s client-server rules, stating that a device can be a client, server, or function as both. The attribute protocol also defines the arrangement of data in the form of attributes, each having a 16-bit attribute handle, a universal unique identifier (UUID), a value, and a set of permissions. It also defined the READ and WRITE operations that one can execute on the attribute stored in the server.Â
- Security Manager Protocol: This protocol ensures communication security between two or more BLE devices. It verifies and authenticates the pairing process. It can also prevent harmful tracking of a deviceâ€™s Bluetooth address by hiding it.Â
- Logical Link Controller And Adaptation Protocol (L2CAP): The L2CAP is vital to the BLE architecture. It functions as a protocol multiplexer by converting multiple protocols into standard BLE packets. It can also break down and recombine large data packets.Â
3. The controller layer
The controller is the physical part of the Bluetooth Low Energy architecture hardware component. It holds the circuit which decodes signals. The chip operates on the 2.4GHz radio band, which it effectively divides into 40 channels. The channels are used for data transmission and sending advertising packets to establish a connection. The controller consists of the physical layer already described and the link-layer that scans, advertises, creates, and monitors communication between BLE devices.
Bluetooth Low Energy has found applications in several areas. One major propelling factor is that it is easy to use without requiring complex or specialized hardware components. Another crucial feature of Bluetooth Low Energy technology is its ability to modulate indoor location and tracking. Unlike the global positioning system (GPS), which deals mainly with outdoor positioning, Bluetooth LE can be effectively used as an indoor positioning system. This has given it a variety of applications such as asset tracking, wayfinding, etc.Â
The sheer simplicity of Bluetooth connectivity and the low power consumption of BLE has also made it indispensable to the internet of things. While power consumption remains a battle in GPS applications of IoT, it has been readily solved using BLE. Specific use cases for Bluetooth Low Energy include:
1. Smart appliances and health or fitness trackersÂ
Fitness trackers and other smart appliances are some of the perfect use cases for Bluetooth Low Energy. The Bluetooth technology creates a wireless network where these devices can connect, transmit, and process information.Â
Bluetooth LE now provides this crucial backbone for the Internet of Things to maintain communication between devices in a sustainable, cost-effective, and reliable way. It means that laptops, smartwatches, phones, smart fitness bands, home appliances, etc., can transmit crucial data without consuming much energy and interfering with the original function of the device.Â
BLE application in personal health goes beyond blood pressure monitors, fitness trackers, and insulin pens that transmit vital information on the amount of insulin injected. Bluetooth LE is a perfect energy-saving alternative for these smart devices in all scenarios.Â
2. Tracking of assets and connected objects
Asset tracking has become another significant application of BLE devices. Tags containing a BLE transmission device are simply attached to a valuable item, and the owners or those in charge are kept abreast of its location at all times. One ideal application of this is airport luggage which one can track with a BLE-enabled device sending a signal to the ownerâ€™s phone.Â
One can also use asset tracking to monitor large cargo, critical medical supplies, office equipment, etc. Once again, the low energy consumption makes it an ideal solution for some of these common problems. Like asset tracking, finding indoor devices in a home or office setting by simply attaching a tag to such items is easy. One can send signals scanned and located by a central device such as your PC, phone, etc.
3. Contact and employee tracing
Bluetooth Low Energy has found another indoor application in contact and employee tracing. Just like item finding, employees and even visitors are given BLE-enabled tags that allow a central device managed by a person to record the location of employees at all times yet maintain their personal privacy. The BLE tags function simply to trace where an individual goes and who they come in contact with. It can help trace the spread of infectious diseases and even space optimization by knowing how much-underused area a company has.Â
Furthermore, BLE tags can be strategic in improving employee safety. For those who are more liable to be in dangerous situations, their tags can have panic buttons that immediately send distress signals with the employeeâ€™s location to the appropriate center.Â
BLE can also help with fall detection for construction sites and seniors in nursing homes. Using the same technology ensures that help is given to those in danger and need as fast as possible.Â
4. Wayfinding and navigation
Wayfinding and indoor navigation are widely used applications of BLE devices. It finds use in vast complexes and facilities such as hospitals, schools, airports, bus or train stations, etc. There are Bluetooth LE beacons set up at different locations to communicate with each other and a visual device that helps direct individuals to the correct site.Â
The individual will often have to download a mobile app that will use the Bluetooth connection between the beacons and the smartphone to identify their present location while directing them on the best possible route. Even more exciting is its use in museums to lead people to items of high interest once they are within range.
5. Proximity marketing
Proximity marketing is another use of BLE technology. It works based on location and closeness to a shop or business. So whenever Bluetooth-enabled devices, which cover virtually every smartphone, are close to a shop, targeted adverts showing their best deals are sent out to attract potential customers nearby. Shopping malls can also use it to inform customers of the location of various retail outlets to make for a seamless and more productive experience.
Bluetooth Low Energy technology has revolutionized the approach to several issues in IoT and other industries. This is because of the peculiar benefits it brings to the table. These advantages of BLE include:Â
- Its low energy consumption significantly prolongs the battery life of BLE-enabled devices.
- It provides encryption of data being transmitted between clients and servers, ensuring data security.
- It can withstand interference on 2.4 GHz because of the frequency hopping technology.Â
- Bluetooth LE 5 models are more robust and have increased speed and range, allowing the BLE devices to operate in congested areas.Â
- The connection and data transfer between BLE devices are rapid (about 3 ms).
- There is a wide range of compatibility between devices manufactured by different companies.Â
On the other hand, while BLE technology represents a much-needed breakthrough, it has limited and specific use cases and does not fit all applications. In some instances, classic Bluetooth connection, Wi-Fi, and other technologies provide a much better solution.Â
Some of the disadvantages and limitations include:Â
- BLE does not perform well over distances more than 25 meters. At optimal conditions, it may extend up to 100 meters but still falls short of the range provided by other technologies (e.g., wide area network or WAN). Thus you canâ€™t use it except for close networks.
- You cannot use it for the transmission of large data packets. Its data rate is limited to 1Mbps and 2Mbps and is not compatible with activities such as video streaming, large file sharing, etc.
- It is open to interference.Â
Bluetooth LE is a foundational technology of our times, found in nearly every connected system and PAN device. For instance, modern smartphones like iPhones and Android devices running OS version 4.3 and above rely on Bluetooth LE. This makes it much more viable to stay connected and support the Internet of Things.Â
For example, keeping a smartwatch synced with your smartphone for hours. We are now witnessing the rise of Bluetooth 5.3 Low Energy (announced in 2021), designed for IoT use cases and battery-driven edge computing devices. This marks the next frontier in the evolution of Bluetooth LE.Â
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