What is Bluetooth Low Energy? How does BLE work?

Bluetooth is a useful technology for data transmission. It is now found in a variety of devices and is popular for everything from streaming music to sharing files.

One downside of Bluetooth is that it uses up quite a bit of battery on the device. If you leave Bluetooth connected all day, the additional power consumption will be huge.

This is especially problematic for devices with limited power, such as Internet of Things devices, or even smartphones.

Bluetooth Low Energy is designed to fix this problem. So, what exactly is BLE and how does it work?

What is Bluetooth Low Energy?

Bluetooth Low Energy is based on Bluetooth. It was released in 2011, and is also known as Bluetooth Smart and Bluetooth 4.0.

BLE is designed to provide many of the same features as Bluetooth but with a focus on low power. Therefore, it is not as fast as Bluetooth and is not suitable for transferring large files. But it is the ideal choice for transferring small amounts of data with minimal power consumption.

BLE has made it possible for a wide range of small IoT devices, such as sensors and tags, to communicate well despite not having large batteries.

How does BLE use less power?

BLE uses the same radio bands as Bluetooth and allows two devices to exchange data in similar ways.

The difference is that BLE devices stay asleep between connections. They are also designed to only communicate for a few seconds when they connect.

This is in contrast to "traditional Bluetooth", which is always on and is designed for continuous communication that often lasts for hours.

Switching off during transmission allows BLE devices to communicate efficiently with a fraction of the power. It's not uncommon for a BLE device to last for a year on a single battery.

What is the difference between BLE and Bluetooth?

What is Bluetooth Low Energy? How does BLE work? Picture 1

BLE is mainly used to save power but there are actually some important differences.

1. Bluetooth provides continuous bidirectional communication. BLE only communicates in short bursts, and some BLE connections only go in one direction.
2. Bluetooth performs data transfer at 1-3MB. BLE is limited to 125KBs-2MBs.
3. Bluetooth has voice capabilities and BLE is not.
4. Bluetooth connection has a latency of up to 100ms. The BLE connection has a latency of 6ms. Remember that the lower the latency, the better.
5. Bluetooth uses 1 Watt power. BLE uses from 0.01 to 0.5 Watt. This means that some BLE devices use 100 times less power.

Do all smartphones support BLE?

As of 2012, almost all smartphones support both classic Bluetooth and BLE. BLE support was introduced in iPhone 4 and Android 4.3. BLE is also supported by most Windows, Linux and Mac devices.

What are Bluetooth beacons?

Bluetooth Low Energy is more than just a tool for data transmission. Arguably the most important application of this technology is the creation of beacons.

A Bluetooth beacon is a hardware transmitter that uses BLE technology to send an ID number every few seconds.

This ID number is then collected by BLE devices in the area. If a device recognizes the ID number, it can connect to the beacon and receive the information.

For example, a beacon can be used to send notifications to any BLE-enabled smartphone that has a specific app installed.

What is Bluetooth Low Energy used for?

BLE will never replace Bluetooth. But it has become the standard technology for many applications.

Smart device

Most smart devices use BLE to communicate with each other. Many smart devices have limited power supply and will not be able to support the use of Bluetooth. BLE is also found in most smartphones, so it provides easy compatibility.

Proximity Marketing (closer marketing)

BLE can be used to send advertising messages to nearby smartphones. This allows for targeted marketing to people based on location. For example, a store can send notifications to people when they walk in.

Indoor location tracking

GPS is obviously effective in location tracking. But it's often not accurate enough to be used in small areas like the inside of buildings. BLE offers a useful alternative to indoor monitoring. When combined with a beacon, it can be used to track smartphones from room to room.

Asset Management

BLE can also be used to track physical items and is therefore popular in asset management. Each item to be tracked is assigned a BLE tag. Then, beacons are set up throughout the facility to 'listen' for the unique ID of each tag.

What is Bluetooth Low Energy not used for?

Traditional Bluetooth is still used for applications that do not prioritize power consumption. Bluetooth is faster and therefore still popular for transferring large files. It is also used for PC peripherals, such as keyboards and headsets, that require constant communication.

How secure is Bluetooth Low Energy?

All BLE connections are equipped with AES-128 end-to-end encryption. This prevents data from being read if it is intercepted.

Man-in-the-Middle attacks are possible, but this can only happen for a limited time when two BLE devices are pairing.

The limited range of BLE also benefits from a security point of view. Any attempt to attack a BLE device would require the hacker to get close to it.

How BLE has changed the Internet of Things

Many of the most popular applications of the Internet of Things would not be possible without Bluetooth Low Energy. By reducing power consumption, it enables IoT devices to be significantly smaller in size and have a longer lifespan.

As a result, BLE powers many of the wearables, tags, and other smart devices we use today. It is likely that BLE will only become more important as more devices begin to connect to each other.

Samuel Daniel

Update 28 December 2021