BLU101 - Introduction to Bluetooth Wireless Communication

Welcome to the new blogpost series of ThingForward. As we are dealing with every field of IoT and wireless communication protocols, there is no denial that bluetooth plays a gigantic role. Today it is not easy to imagine our lives without bluetooth devices. Bluetooth entertainment systems, smartphones, cars, home control systems, gaming consoles, lighting solutions and many more applications can be controlled over this protocol. The official website says that, 4 billion bluetooth devices will be shipped this year.

As the new releases come up, power consumption is decreased and the signal quality is increased day by day. Today we will show you the technical background of bluetooth, what are being developed, the versions, before we start to program with bluetooth devices on upcoming blogposts. So, let's start!

Image 1: Bluetooth Logo

Bluetooth technology had been first initiated in 1989, called "short link radio technology" that time, by Ericsson Mobile's CTO Nils Rydbeck and Johan Ullman. This project had been started for wireless headsets and after several researches, the first consumer bluetooth was launched at 1999. It has been 20 years now, bluetooth technology is still getting over and is developed rapidly.

We talked about 3GPP association during our 5G and NB-IoT blogposts. Bluetooth also has its own group called Bluetooth Special Interest Group, consist of more than 30000 member companies. Hint: IEEE 802.15.1 is a standardised version of Bluetooth that doesn't manage the standards anymore.

Specifications:

  • Operation Frequency: 2402 MHz - 2480 MHz
  • Operation Frequency: 2400 MHz - 2483.5 MHz with guard bands.
  • Modulation Type: Mostly "Gaussian Frequency-Shift Keying" or 8 (Differential Quadrature Phase-Shift Keying)
  • Band: Globally unrestricted, unlicensed
  • Data Transmission: Data packs, over 79 channels
  • Channel Bandwidth: 1MHz
  • Frequency: 1600 per second during transmission

Hint: Bluetooth uses a radio technology called frequency hopping spread spectrum.

Bluetooth 5.0

Every new release of Bluetooth provides the improvements to the protocol. Just like LTE, Bluetooth is also being updated in regular basis, and the latest version is called BLE 5.0! These pros can be summarised as:

Longer Range: The communication range was improved from 30 meters (Bluetooth 4.2) to 150 meters, which is great for IoT applications.

Double Transmission: The data can be transmitted to two different devices at the same time. As an example, one smartphone can be paired with two different sound systems.

Higher Speed/Throughput: Bluetooth 5.0 doubles the data transmission speed of Bluetooth 4.0. Beacon Support: By using the location services, the host can send messages/notifications to the devices in the same area. As an example, a fast-food chain can notify its customers by sending notifications including discounts or offers. According to SIG reports, nearly 40 billion hardware which has Beacon support are being shipped by 2020.

Bluetooth 5.0 and IoT

As we get deeply tied up with IoT, we have already implemented it during our projects as communication method in order to pair our smart modules with smartphones. There are plenty of hardware solutions for this protocol and reaching the good and affordable bluetooth hardwares is not a big deal, but power consumption is a big challenge for IoT. Bluetooth has two different versions, the Bluetooth Classic and low power version, a.k.a. BLE. Since the sensors and the MCUs are mainly operated with batteries, BLE became a common protocol for IoT. No need to say, the BLE is the best version for applying them in IoT field, thanks to its low power consumption.

Hint: The communication between Bluetooth Classic and BLE is not possible, so the smartphones for instance, they have dual mode for bluetooth devices.

Hardware

As we are speaking about IoT, the prototyping is the first step of digging Bluetooth and its applications for IoT. There are plenty of hardware producers on the market. The best method to select the hardware, you need to think about:

  • Your budget
  • The supported version of BLE
  • Number of digital I/O and peripherals
  • The dimensions
  • The software support i.e. libraries
  • Compatibility with other devices that you want to use

The first suggestion would definitely be Adafruit Feather Bluefruit NRF52 board, which has an ARM Cortex M4F chip. It has plenty of software examples, library support and QAs in Adafruit community. This board also supports Adafruit mobile applications like nRF Beacon(iOS, Android), BLE UART controller and so on. For more information, please visit the official website of nRF52.

If you are dealing with a small device during your prototyping, then you may want to consider a smaller CPU. Bluno Beetle BLE! Bluno Beetle is the smallest Arduino-based Bluetooth board in the market. You can directly start to code with Bluno and with your loyal Arduino IDE. If you don't need a lot of peripherals, Bluno Beetle could be the board you need!

Conclusion

Our smartphones, cars, multimedia systems and countless other systems are already equipped with Bluetooth support. The more improvements in power consumption and communication ranges it gets, the wider usage area will it have in the end. It gives the possibility to the end user to control everything with the smartphone or similar. The upgraded communication range of 150 meters shows how efficient would it be for IoT applications.

On the next blogposts, we will show how to program Bluetooth boards. Stay tuned for learning how to program Bluetooth devices!

Eren Mert Irez

References:

[1] Wikipedia Bluetooth [2] Bluetooth Official Website [3] IoT4All [4] LifeWire