Bluetooth Low Energy (BLE) is one of the most widely used low-power connectivity standards. BLE has entered our lives with Bluetooth 4.0 and is especially suitable for IoT-based applications. Take a look at the article to find out more.
What is Bluetooth Low Energy?
We can think of BLE as a type of Bluetooth that uses less power or energy. It is an environmentally-friendly version of it and one of its main purposes is to facilitate the Internet of Things projects. An example of Bluetooth usage, which everyone probably has little knowledge of, is the wireless speaker you connect your phone to, which allows you to manage the volume. This is version 4 of BLE.
What is the difference between Classic Bluetooth and BLE?
Classic Bluetooth and BLE are similar in that they help customers connect to their devices. But the differences begin in how they distribute data to save energy. Classic Bluetooth can handle a lot of data, but the device’s battery drains quickly and therefore it’s much less practical. BLE is used for applications that do not require large amounts of data exchange and can run on battery power for years at a cheaper cost. In short, BLE is a standalone standard that is not compatible with classic Bluetooth. You can see some differences in the figure below.
Why BLE is Perfect for IoT?
The Internet of Things (IoT) refers to a network of devices that collect and exchange data wirelessly. For these devices to function efficiently, they need:
- Long battery life
- Reliable wireless communication
- Small form factor
- Secure data transmission
BLE checks all these boxes. It’s optimised for short bursts of data, meaning it wakes up, sends/receives data, and goes back to sleep—conserving energy. And because BLE is already integrated into most smartphones and tablets, it becomes easier to implement and manage.
Usage and applications of BLE in IoT
BLE’s superior energy efficiency has made it a popular choice for IoT applications. BLE is more energy-efficient than other standards (for example ZigBee, Bluetooth classic, and Wi-Fi). This means that these devices will work for more extended periods when running on batteries. There are many IoT applications based on BLE. Here are a few examples:
- We see smartwatches in many different brands. BLE is commonly used to connect these smartwatches to other things.
- Beacons: It is a technology that provides location information using BLE. Products or devices with beacon technology can interact with nearby smartphones by emitting passive signals. This technology, which reaches people depending on the distance, can transmit the desired information to the people with whom it interacts.
- Some healthcare devices, such as glucometres, insulin pumps, and heartbeat sensors, also use the BLE connection.
- Finally, many devices we use in Smart Home systems are also good examples of BLE usage.
Technical Architecture of BLE in IoT
A BLE network in IoT consists of central and peripheral devices:
- Peripheral Devices: These are sensors or small devices that advertise their data.
- Central Devices: Usually a smartphone or gateway that scans for and connects to peripherals.
When a peripheral advertises, the central device picks up the signal, initiates a connection, and data transfer occurs. After the task, both devices return to low-power mode.
Advantages of Using BLE in IoT
1. Low Power Consumption
BLE devices spend most of their time in a deep sleep state and wake only to send or receive brief data bursts. This design allows sensors and wearables to operate for months or even years on a single coin‑cell battery, minimising maintenance and ensuring uninterrupted monitoring.
2. Widespread Support
Nearly all modern smartphones, tablets, and laptops come with built-in BLE radios. This ubiquity eliminates the need for extra gateways or adapters, making it easy for users to pair and control IoT devices through familiar interfaces and apps.
3. Low Cost
BLE chipsets are inexpensive and readily available, which keeps material costs down. Manufacturers can integrate reliable wireless connectivity into products without significantly raising the retail price, supporting larger-scale deployment.
4. Flexible Topologies
With Bluetooth Mesh, BLE devices can form many-to-many networks where each node relays messages. This self-healing, scalable topology is ideal for smart buildings, warehouses, and city-wide IoT installations, ensuring that data travels even if individual nodes fail.
5. High Security
BLE supports industry-standard AES-128 encryption and multiple secure pairing methods. Features like random address rotation and privacy modes protect data from eavesdropping and unauthorised tracking, essential for sensitive applications like healthcare.
6. Ease of Development
A rich ecosystem of SDKs, libraries, and reference designs accelerates prototyping and production. Developers can leverage well-documented APIs and sample code to connect sensors, configure mesh networks, and integrate BLE communication with minimal learning curve.
Challenges and Limitations of Bluetooth Low Energy
1. Signal Range Variability
While BLE can reach up to 100 metres in open space, physical obstacles such as walls, metal structures, and radio interference can drastically reduce effective range. Careful planning of device placement and network topology is necessary to maintain reliable coverage.
2. Limited Data Throughput
BLE is optimised for low-bandwidth transfers—sending small packets of data at low rates. Even with the 2 Mbps option in BLE 5.x, it remains unsuitable for continuous high-volume needs like video streaming or large file transfers.
3. Battery Degradation
Poorly tuned firmware or hardware configurations can lead to excessive power draw. Improper advertising intervals or connection parameters may unexpectedly drain batteries, so thorough power profiling and firmware optimisation are essential.
4. Compatibility Issues
Some legacy or industrial devices may not support modern BLE standards. In environments with older controllers or specialised equipment, additional hardware or protocol bridges may be needed to ensure seamless interoperability.
Conclusion
Bluetooth Low Energy (BLE) has matured from a niche wireless protocol into a foundational pillar of the Internet of Things. Its hallmark combination of energy efficiency, security, affordability, and interoperability makes it uniquely suited to the evolving demands of connected ecosystems.
As BLE integrates with AI, edge computing, and advanced mesh capabilities, it will drive transformative innovations in healthcare, manufacturing, agriculture, smart homes, and beyond.
Looking forward, BLE’s continuous evolution—fuelled by enhancements in speed, range, and functionality—will ensure it remains central to digital transformation strategies. In a world hungry for efficient, resilient, and secure connectivity, BLE’s low‑energy promise stands as a beacon guiding us toward smarter, more sustainable, and deeply connected futures.
Frequently Asked Questions About The Usage of BLE and IoT
Q1. Can BLE work without Internet?
Yes. BLE devices communicate directly with one another over local connections using radio links. No internet connection is required for peer-to-peer data exchange or sensor reporting within the BLE range. However, if you wish to upload data to a remote server or enable remote control, a gateway or smartphone with internet access can bridge BLE data to the cloud.
Q2. Is BLE secure?
BLE incorporates multiple security measures, including Secure Simple Pairing for robust key exchange, AES-128 encryption for data privacy, and randomised device addresses to prevent tracking. That said, implementing proper bonding procedures, firmware updates, and secure boot processes is essential to maintain strong end-to-end security.
Q3. Can BLE and Wi-Fi be used together?
Absolutely. Many IoT devices leverage both technologies: BLE for low-power neighbour discovery, pairing, and short-range data transfer, and Wi-Fi for sustained, high-bandwidth communication to cloud servers. For instance, a smart speaker may use BLE to simplify initial setup via a mobile app, then switch to Wi-Fi for audio streaming.
Q4. What’s the lifespan of a BLE-powered device?
Device longevity depends on use case, advertising intervals, connection parameters, and battery capacity. Under typical sensor-reporting scenarios, devices can operate anywhere from six months to ten years on a single coin-cell battery. Tweaking firmware settings and power management strategies helps extend battery life.
Q5. How many BLE devices can connect to one hub or phone?
The maximum number of simultaneous connections varies by hardware and software stack. Many smartphones can maintain 5–20 active BLE connections concurrently, while dedicated gateways and microcontrollers can support dozens to hundreds of connections, depending on memory, processing power, and BLE stack capabilities.
