Getting Started With BLE – A Complete Guide

Going down memory lane, Bluetooth and its applications have been used since the 2000s. Since its development and usage, Bluetooth has undergone numerous changes and advancements. One of the most important of them is the development and introduction of Bluetooth Low Energy.

Bluetooth Low Energy is abbreviated as BLE (Bluetooth Low Energy, and is also marketed as Bluetooth Smart). Bluetooth Low Energy (BLE), sometimes known as Bluetooth Smart, maybe a lightweight subset of original Bluetooth that debuted with the Bluetooth 4.0 core specification. 

In this article, we are going to talk about Bluetooth Low Energy Technology which will help you in getting started with BLE.

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What Is Bluetooth?

Before diving into the small print of Bluetooth Low Energy, it is essential for us to understand the meaning and dealing of Bluetooth. The Bluetooth specifications specify the technical components developers utilize to build the interoperable devices that structure the thriving Bluetooth ecosystem.

Watch our video on Know Everything About Bluetooth Low Energy Technology below👇

The Bluetooth Special Interest Group (SIG) oversees Bluetooth specifications, which are updated and improved daily by Bluetooth SIG Working Groups to satisfy changing technology and market needs.

Most people associate Bluetooth with a wireless headset or another gadget that connects you to the information you are transmitting. Bluetooth is a wireless connection between your phone and the device to which you are linked. This mechanism allows data to be sent over small distances without using cables.

What Is Bluetooth Low Energy?

Bluetooth gadgets are continually being developed and reinvented. Do you recall when Apple initially released AirPods? There are now various versions of this Bluetooth connectivity device, including innovations that help with battery life, which leads us to Bluetooth Low Energy.

BLE (Bluetooth Low Energy) is a type of wireless communication designed for short-range communication. Like Wi-Fi, BLE allows devices that are connected to interact with one another. 

BLE is designed for circumstances where battery life is more important than high data transfer speeds. Assume you would like to broadcast marketing campaigns within the vicinity of a just-introduced headset.

As the quantity of data and information you send to a visitor’s smartphone is minimal, BLE-enabled beacons can do the task fast and without exhausting the battery. 

Bluetooth Low Energy vs. Bluetooth Classic

  • Both are accustomed Connect the devices and Transferring the info for private and commercial use.
  • The main difference is how they’re distributing data for low-energy power.
  • Bluetooth classic is employed to transfer many data continuously but contains high power and more cost.
  • BLE transfers smaller packets of information over short periods of your time using low battery power.

Bluetooth Classic vs. Bluetooth Low Energy

Key Terms And Concepts

  1. Generic Attribute Profile (GATT) :
    The GATT profile could be a general specification for sending and receiving short pieces of information called “attributes” over a BLE link. GATT supports all current BLE app profiles.
  2. Generic Access Profile (GAP) :
    GAP is mandatory for BLE devices as it defines a framework for enabling device discovery, security, connectivity, and related network technologies. This defines the role that the Connection can implement.
  3. Profiles :
    Profiles can be specifications that show how the tool works in a particular application. Note that a tool can implement quite one profile. For example, a tool could contain a vital sign monitor and a battery level detector.
  4. Attribute Protocol (ATT) :
    GATT is made on top of the Attribute Protocol (ATT). ATT is optimized to run on BLE devices. Up to this point, use as few bytes as possible. Each attribute is uniquely identified by a Universally Unique Identifier (UUID). This can be in the standardized 128-bit format of the string identifier used to identify the information uniquely. The attributes transported by ATT are formatted as characteristics and services.
  5. Characteristic :
    The lowest level concept in GATT transactions is the Characteristic, which encapsulates one datum. Similar to Services, each Characteristic distinguishes itself via a pre-defined 16-bit or 128-bit UUID. Characteristics are the most point that you will interact with along with your BLE peripheral, so it is vital to grasp the concept. They also want to send data back to the BLE peripheral since you’re also ready to write to characteristics.
  6. Descriptor :
    Descriptors are defined attributes that describe a characteristic value.
    For example, a descriptor might specify a human-readable description, an appropriate range for a characteristic’s value, or a unit of measure specific to a characteristic’s value.
  7. Service :
    Services are accustomed to breaking data into logical entities and containing specific chunks of information called characteristics. A service can have one or more characteristics. Every service distinguishes itself from others using a singular numeric ID called a UUID, which may be either 16-bit or 128-bit.

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BLE Operations

You must communicate with the BLE device to perform any action or operation. Therefore, BLE communication can be combined into three operations.

  1. Read:
    When this property is enabled, the app will read the value of the property or descriptor of the BLE device and interpret it based on the previously created protocol.
  2. Write :
    We can write data 2 ways:-
    Write With The Response: If you enable this property, you can write characteristic values ​​and get confirmation from the BLE device after completing the process.
    Write Without Response: If you enable this property, you can write characteristic values, but you will not receive confirmation from the BLE device after the operation is complete.
  3. Notify / Indicate:
    Both are a way for the peripheral to notify the medium when the feature value changes. The only difference between notifications and indications is that notifications need to be accepted by the client when receiving a package, while indicators require this type of acceptance. So it moves slowly.

GAP Roles

GAP is a topology for maintaining connectivity between BLE devices and the devices that control BLE devices. GAP roles can be defined in two ways.

The first one is Broadcasting or connectionless.
The second one is Connecting or connection-oriented.

Broadcasting OR ConnectionLess

  1. Broadcaster :
    Devices with the sender role only send data to this environment. This is done through continuous advertising and usually contains useful data in your ad package, that is, data that is visible to everyone. Such devices do not require a receiver and do not accept connections, as their sole job is to send them to others.
  2. Observer :
    Observers are the opposite of broadcasters. Observers passively listen to nearby BLE devices and process the data in their ad packets. No transmitter is needed as it does not broadcast anything and does not connect.

Connecting OR Connection-Oriented

  1. Peripheral Devices :
    BLE peripherals are generally low-power devices. Peripherals can be scanned with a Bluetooth central device. When Connection is established, the peripheral act as an enslaved person. Smartwatches, bracelets, sensors, fitness bands and smart light bulbs are examples of peripherals.
  2. Central Devices :
    The central device is usually a high-power energy device. A hub is a device that searches for Bluetooth devices and connects to and uses the information they contain. Central devices are typically richer in resources, such as computing power, than peripheral devices. Pre-attached: The device is designated as the central device at boot time and as the master after it is connected. Laptop, mobile, and tablet devices are examples of core devices.

How Does Bluetooth Low Energy Work?

GATT is an acronym for Generic Attribute Profile, which uses services and characteristics to define how two Bluetooth Low Energy devices exchange data. GATT works when a dedicated connection is established between the two devices. This means that you have already completed the GAP-regulated advertising process.

The most important thing to note about GATT and connections is that the connections are exclusive. BLE peripherals can only connect to one central device (such as a mobile phone). When a peripheral connects to a central device, it stops advertising itself, and other devices cannot recognize or connect to it until the existing connection is broken.

Establishing a connection is also the only way to enable two-way communication. In this case, the central device can send meaningful data to peripheral devices and vice versa. The operation of BLE can be divided into three sections described below and will help you understand how Bluetooth low energy works.

Attribute And Data Hierarchy

How Does Bluetooth Low Energy Work?

Attributes are the smallest data entity defined by GATT (and ATT). These are addressable information that may contain relevant user data (or metadata) about the structure and grouping of the various attributes contained in the server. GATT and ATT work only on attributes, so all information must be organized in this format for the client and server to interact.

The attributes of the GATT server are grouped into services, and each service may contain zero or more characteristics. These features can contain zero or more descriptors. The “Important Terms” section above discusses the relationship between services and features.

Most data types in the GATT hierarchy must distinguish between their definitions (the entire set of attributes that make them up) and their declarations. Declarations are the single attribute that always comes first (in ascending order of handles) in the definition and introduces most of the metadata for subsequent data.

All declarations have read-only permissions that do not require security because they cannot contain sensitive data. These are just structural attributes that allow the client to understand and discover the server’s layout and type of attributes.

Central And Peripheral Communication

How Does Bluetooth Low Energy Work?

A central device and peripheral devices are required to perform BLE operations. Peripherals advertise themselves and contain information. The central device scans for ad packages. Once connected, you can perform BLE operations. The central device can perform read and write operations if peripheral functions give this permission.

BLE technology acts as an intermediary between both types of devices. When operating with BLE peripherals, notification/display operations can be performed on the central device. This type of surgery is useful for all kinds of emergencies.

Example Service

How Does Bluetooth Low Energy Work?

This section provides examples of specific services found in many commercial products today. Heart rate service (HRS) relays your heart rate to a monitoring device.

This heart service has several features, each with a descriptor. The structure of the attributes is as follows:

Attribute Handle

The attribute handle is a 16-bit unique identifier:

  • Makes the attribute “addressable.”
  • Does not change.

Handle values ​​grow in an ordered order on the server (gap allowed) and during the discovery process Detected by the client.

Attribute Type (Universally Unique Identifier (UUID))

The attribute type determines the data type present in the attribute’s value and uses a 2-byte or 16-byte UUID. Here is an example:

  • Service UUID
  • Characteristic UUID
  • Profile UUID
  • Vendor-Specific UUID

Attribute Value

The attribute value contains the actual data content that the client can access. You can also include metadata about the attribute (depending on the type).

Attribute Permissions

Attribute permissions are attribute metadata that specifies:

  • ATT access operations are allowed on attribute values. The allowed operations are read and write, no operations.
  • Security requirements. In this case, encryption is required. Cryptography has different types of layers that are also needed for security. Authentication is also required for security, such as biometrics and password authentication.

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Applications Of BLE In The Real World

Next, I will explain where BLE can be used/applicable in the real world. Therefore, BLE can be used in different personal and professional applications. Makes our lives easier.

  • Wireless charging
  • Medical service
  • Smart Kitchen
  • Smart Tags
  • Mobile payments concept
  • Track a pet’s behavior
  • Automotive industry
  • Home automation systems.

What Makes Bluetooth Low Energy (BLE) Different?

Bluetooth Low Energy is a separate Bluetooth standard incompatible with conventional Bluetooth. The latter was originally commercially released almost 20 years ago, and the Bluetooth Special Interests Group (SIG) is no longer actively developing it.

Not being developed certainly does not imply not being used. It is commonly found in devices that demand a constant connection, mostly audio devices such as wireless speakers and headphones. 

The main distinction between Bluetooth Low Energy and Bluetooth is Bluetooth Low Energy’s ability to consume less energy. Compared to traditional Bluetooth, BLE is designed to use significantly less power and cost while retaining a similar communication range.

Applications with minimal energy consumption can run on a small battery for longer periods. Although this is inconvenient when talking on the phone, it is critical for applications that regularly transmit small amounts of data.

Bluetooth Classic is meant for continuous two-way communication, but Bluetooth Low Energy (BLE) sends smaller data packets over shorter durations. Just as the name implies, Bluetooth Low Energy consumes far less energy, up to 100 times less than Bluetooth Classic.

Bluetooth Classic, on the other hand, provides a bigger range and higher data throughput because it is not as constrained. Bluetooth Low Energy is natively supported by mobile operating systems such as iOS, Android, Windows Phone, and BlackBerry, as well as macOS, Linux, Windows 8, and Windows 10.

The Specification

With version 4.0 of the Bluetooth Core Specification, the Bluetooth SIG launched Bluetooth Low Energy in June 2010. The specification had been in the works for some years, and the majority of the contentious portions and decisions had been smoothed out by the companies engaged in the development process, with a few minor problems remaining to be addressed in future revisions.

Bluetooth 4.1, the first significant update, was launched in December 2013 and is the current standard for BLE app development. Although the essential building blocks, procedures, and concepts remained unchanged, this release included several updates and enhancements to improve the user’s experience.

4.1 is backward compatible with 4.0, as are other Bluetooth specifications, ensuring proper interoperability between devices that implement multiple specification versions. The specifications allow developers to release and qualify products for either version.

However, thanks to the rapid adoption of the latest specification releases and, therefore, the incontrovertible fact that the 4.1 version standardized several common practices among devices, it is recommended that developers target the foremost recent version available.

Unless otherwise stated, the Bluetooth 4.1 specification is employed as a reference during this work. We shall specify when the preceding 4.0 standard does not cover a given region wherever relevant, especially when describing a notable modification or addition.

Bluetooth Low Energy (BLE) technology appears to take the world closer to universal internet connectivity. Classic Bluetooth, used in mobile phones in-car hands-free devices, is notorious for consuming a lot of power.

Bluetooth LE, part of the Bluetooth Special Interest Group’s (SIG) current Bluetooth 4.1 protocol, is significantly less power-hungry. It is claimed that ordinary slave nodes running Bluetooth LE can function for months or even years on a single coin cell.

Part 1 of this guide offers an in-depth and detailed description of the specifications, adaptations and other aspects of BLE. With a set of useful attributes and functions, BLE also comes bearing some limitations that must be highlighted. The following section of the article talks about the same.

Key Limitations

  • First and foremost, Bluetooth LE does not provide Classic Bluetooth-style functionality in a more energy-efficient format. It does not allow designers to obtain Classic Bluetooth functionality without a significant power drain suddenly. If a specific design requires Classic Bluetooth capabilities, such as over-the-air streaming of audio or other data at data rates of 1Mbps or greater, the same high-power budget will be required.
  • Bluetooth LE is designed for a very specific range of applications. This technology makes the lightning-quick connection, the transmission of short bursts of tiny packets of data, and lightning-quick disconnection possible. This ability to send ‘pulsed’ data is ideal for communicating morsels of information like ‘the temperature in the refrigerator has climbed above 5°C,’ or ‘the room is not occupied.
  • Only three of a Bluetooth LE device’s 40 radio channels are needed to advertise its presence to other Bluetooth devices (rather than 32 in Classic Bluetooth), implying that its advertising transmissions are substantially faster (1.2ms rather than 22.5ms) than Classic Bluetooth.37 data transmission channels can readily avoid interference and keep transmission times short. Of course, the operation of Bluetooth LE is not by chance: the radio’s capacity to spend lengthy periods in deep sleep mode is due to a combination of pulsed transmission capability and the freedom to hop across frequency channels, allowing for quick interference-free communications.
  • Bluetooth LE will be utilized only to send ‘state’ data rather than streaming content. Although Bluetooth LE devices may specify a theoretical maximum data rate in bits per second if an application’s designer is forced to think about ‘data rate,.’Bluetooth LE is the incorrect technology for the job. A decent Bluetooth LE application is one in which the Bluetooth radio is turned off practically all the time.

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Network Topology

Bluetooth Low Energy devices can communicate with different devices by using two different network topologies: Broadcasting and Connections.

  • Broadcasting 

Using connectionless broadcasting, you can send data to any scanning device or receiver within listening range. This technology essentially allows you to send data to anyone or anyone who can pick up the communicated data.

Broadcasting is crucial to comprehend since it is the only means for a device to simultaneously send data to several peers. You can broadcast data by using BLE’s advertising features. Broadcasting is quick and simple to use, and it is an excellent option if you simply need to send a small quantity of data to several devices regularly.

When opposed to a conventional connection, one of the key disadvantages of broadcasting is that there are no security or privacy safeguards; that is, any spectator device can receive the data being broadcasted; hence the broadcasting topology may not be suitable for sensitive data.

  • Connections 

Connections are one of the most widely used network topologies, which is convenient and better and establishes a secure bidirectional one-to-one (1:1) data transfer link. A peripheral/ central GAP roles pair is required to make a BLE connection.

The peripheral GAP function uses as little computing power and memory as possible. Most of the time, this is the job chosen for the device under development. A central device receives connectable advertising packets from a peripheral and makes a request to the peripheral to establish an exclusive connection between the two devices to commence a connection.

The peripheral stops advertising once the connection is established, and the two devices can begin exchanging data in both directions. A connection is thus nothing more than the periodic data exchange between the two peers involved in it at certain times (connection events).

It is worth noting that, while the center is the device that handles connection setup, data can be transmitted independently by either device during each connection event. The roles have no bearing on data throughput or priority. 



In conclusion, Bluetooth and Bluetooth Low Energy are comparable in that they allow users to connect to their favorite and most significant gadgets for personal and business use. The difference is in how they disseminate energy-saving data.

Bluetooth can handle a lot of data, but it uses up a lot of battery life and is much more expensive. Bluetooth Low Energy is used for applications that do not require huge volumes of data interchange and may run for years on battery power at a lower cost.

Bluetooth LE has now entered the mainstream and is poised for widespread adoption, displacing older, more sophisticated, and power-hungry technologies. We hope this article helps you in getting started with BLE technology.

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