Bluetooth Low Energy (BLE): A Power-Efficient Connectivity Solution for the Internet of Things (2024)

This article focuses on "Bluetooth Low Energy (BLE)", a wireless technology designed for low-power devices that necessitate short-range communication while conserving battery life. This technology has been widely adopted in various applications, including wearables, medical devices, industrial automation, and home automation. You should read this article if you want to gain a better understanding of BLE technology. If you want to know why BLE has gained a great role in the context of IoT. Or if you want to know who King Harald Gormsson was.

If you are currently struggling with the question whether BLE is the right wireless technology for your new product or how to best integrate BLE into your existing hardware, please feel free to make an appointment with our experts on the topic.

General overview

The Bluetooth Low Energy (LE) radio is designed for very low power operation. Transmitting data over 40 channels in the 2.4GHz unlicensed ISM frequency band, the Bluetooth LE radio provides developers a tremendous amount of flexibility to build products that meet the unique connectivity requirements of their market. Bluetooth LE supports multiple communication topologies, expanding from point-to-point to broadcast and, most recently, mesh, enabling Bluetooth technology to support the creation of reliable, large-scale device networks. While initially known for its device communications capabilities, Bluetooth LE is now also widely used as a device positioning technology to address the increasing demand for high accuracy indoor location services. Bluetooth LE now includes features that enable one device to determine the presence, distance, and direction of another device. [1]

History of BLE creation

The first official version of the Bluetoth standard was released by Ericsson in 1994. The developers named their invention in honor of the king of Denmark, Harald Gormsson, nicknamed “Blue-tooth,” who united the warring Danish tribes into a single kingdom in the 10th century. The Bluetooth logo is a mix of the Nordic runes for H and B (Harald Bluetooth).

There are currently two types of Bluetooth enabled devices:

1. Bluetooth Classic (BR/EDR), used in wireless speakers, car infotainment systems and headphones.
2. Bluetooth Low Energy (BLE), which was introduced in the Bluetooth 4.0 version of the standard. It is most often used in applications that are power-sensitive (such as battery-powered devices) or in devices that transmit small amounts of data with long gaps between transmissions (such as a variety of environmental sensors or control devices such as wireless switches).

These two types of devices are not compatible with each other, even if they are released under the same brand or specification. Bluetooth Classic enabled devices cannot communicate directly with devices using BLE. This is the reason why some devices, such as smartphones, come with support for both types of connection (so-called Dual mode Bluetooth devices), allowing them to exchange information with both types of devices. [3], [4]

Today, BLE is used in a wide range of applications, including wearables, medical devices, industrial automation, and home automation. Its low power consumption and small footprint make it an ideal choice for IoT devices that require wireless connectivity with minimal power consumption. As technology continues to evolve, BLE is likely to play an increasingly important role in the development of new IoT devices and applications. [2]

Technical facts

• frequency range: 2.400–2.4835 GHz
• Nominal max. range: <100 m
• The maximum data transfer: 2 Mbit/s
• Minimum total time to send data: 3 ms
• Peak current consumption: <15 mA [5]

Key Features of BLE

Bluetooth Low Energy (BLE) is a wireless communication technology that is designed for low-power devices that require short-range communication with minimal battery consumption. Here are some of the key features of BLE:

• Low power consumption: BLE is designed to be extremely power-efficient, allowing devices to operate for long periods of time on small batteries or even energy harvesting sources.
• Short-range communication: BLE operates over a short range, typically up to 10 meters, making it ideal for communication between nearby devices.
• Fast connection and data transfer: BLE devices can connect quickly and transfer data at high speeds, making it suitable for use in real-time applications.
• Security: BLE provides a range of security features, including encryption and authentication, to ensure that data transferred between devices is secure.
• Interoperability: BLE is a standard protocol that is supported by a wide range of devices, making it easy for different devices to communicate with each other.
• Cost-effective: The low-power requirements of BLE mean that it is cost-effective to implement devices with limited processing power and memory.
• Simple protocol stack: The protocol stack used by BLE is relatively simple, consisting of the Physical Layer (PHY), Link Layer (LL), Host Controller Interface (HCI), and the Generic Attribute Profile (GATT).

BLE is an ideal communication technology for a wide range of low-power IoT devices, including wearables, medical devices, industrial automation, and home automation. Its low power consumption, fast connection and data transfer, and strong security features make it a popular choice for IoT applications. [2]

Differences between Bluetooth Classic and BLE

BLE uses about 1/10 of the energy Bluetooth devices use. BLE achieves this by constantly being in ‘sleep mode’ until a connection is initiated. If devices need a more extended range to operate, they should be using Bluetooth, but BLE should be used if they need to run for longer periods over shorter distances. BLE excels at transmitting small and infrequent data packets using low amounts of power and low latency, while Bluetooth excels at continuously transferring large amounts of data. Bluetooth connection times are ~100ms, while BLE connection times are only a few mS — making connections to BLE much faster than standard Bluetooth devices. BLE devices can connect with a larger number of other devices, compared to standard Bluetooth. [6]

Advantages of BLE

• It offers very low power consumption and hence battery life can be very long. This is due to the fact that both master and slave devices can go to deep sleep mode between transactions. Master informs slave about hopping sequence and when to wake up.
• It can be used for small size data transfer specially in IoT (Internet of Things) based applications. It offers maximum upto 255 bytes of message capacity.
• It offers security using 128 bit AES algorithms. Hence encryption is applied to data being communicated between master and slave devices.
• It uses frequency hopping using 2.4 GHz band, hence it can withstand against interference. Moreover advertising channels are chosen to be different than wifi channel frequencies to avoid interference between wifi and bluetooth devices.
• The BLE devices are robust to operate in congested environment due to introduction of V5.0
• It offers reliability and enables digital life.
• BLE beacon devices have become popular due to speed and range increase in bluetooth 5.0 version.
• Connection establishment procedure and data transfer is very fast (about 3 ms).
• Devices from different manufacturers are compatible with the others.
• There are endless devices using BLE and are inexpensive too. [7]

Disadvantages of BLE

• It can not be used for higher data rates as offered by wifi and cellular technologies. It supports 1 Mbps & 2 Mbps data rates.
• It can not be used for long distance wireless communications unlike cellular and wifi devices. It supports upto 200 meters in LOS (Line of Sight).
• It is open to interception and attack due to wireless transmission/reception. [7]

Summary

Bluetooth Low Energy (BLE) technology, has evolved into a versatile communication protocol with applications in IoT devices. Its key features include low power consumption, short-range communication, and fast data transfer. BLE's advantages encompass security, reliability, and compatibility, leading to its widespread use in wearables, medical devices, and automation. However, it differs significantly from Bluetooth Classic, excelling in energy efficiency and faster connection times but with limitations in data rates and communication distance. Despite drawbacks, BLE continues to be a preferred choice for various low-power IoT applications.

At deveritec, we're having solid experience with BLE technology. During several projects this year we're implemented it into a variety of smart home and industrial devices. We can implement complex and composed solutions with this technology.

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