BLUETOOTH LOW ENERGY (BLE) OVERVIEW

The Bluetooth Low Energy Protocol (also known as BLE or Bluetooth Smart), was first introduced by Bluetooth SIG along with the Bluetooth 4.0 version (2010).

The BLE protocol allows a wireless data transfer with “low energy” devices (Beacons); once in function, they keep listening to the channel until a device requests a connection with them.

BLE Beacons broadcast data packets via wireless (through the 2,4GHz band) spaced out by configurable time frames (Broadcast Interval).  This emitted data string is called Advertising Packet. The connection to the Beacon occurs through the Master/Slave principle. (the same principle used by Bluetooth Classic). The Master has the job to handle the communication (start, synchronization, end), while the Slave only performs the Master orders. The Master can open multiple connections with Slaves at a time, but a  Slave can be connected with only one Master at a time.

An example of Master/Slave architecture is the communication between Smartphone and Beacon: The smartphone (Master, with a Bluetooth 4.0 chip or higher) keeps listening to the channel where the Beacons (Slave) send their own Advertising. Once it receives an Advertising, the Smartphone can perform a connection with one or more Beacons at a time (maximum 8).

An example of data sending between Master and Slave during Connection Mode

By remaining dormant most of the time, Beacons have an extremely reduced battery consumption compared to a Bluetooth Classic device (also due to the small amount of data sent during the connection and the dormant period). This allows these devices to be powered by small energy sources (such as a coin-cell), and to have a  long life expectancy (from months to several years).


BLUETOOTH LOW ENERGY VERSIONS (BLE)

  • It is the first protocol that introduced the low energy version (2010).

  • Faster than the previous version.
  • Fixes the interference problem with 4G/LTE.
  • Backward compatible with previous versions.

  • Allows chips to use Bluetooth over the l’Internet Protocol Version 6 (IPV6), for a direct Internet access.
  • Devices that implement the BR/EDR Core Configuration will be backward compatible with all the previous Bluetooth Core Versions that implement the same technology (starting from 1.1).
  • Compared to previous versions, Bluetooth 4.2 allows a faster throughput (250% more than 4.0 e 4.1 versions).
  • The packets capacity has been incremented 10 times more than previous versions.
  • With more efficent and secure features, Bluetooth 4.2 allows only trusted users to track devices and communicate with them.
  • Backward compatible with previous versions.

  • Doubled velocity speed (from 1Mbps to 2Mbps), and increased reading range up to 4 times with same power (these features can’t coexist, only one at the time).
  • Data size that can be sent over a Beacon increased to 255 bytes.
  • The use of the long reading feature drastically reduce the trasmission speed; That’s because greater is the distance, greater is the probability some bits will be lost, and perform the necessary controls reduce the amount of bits that can be sent.
  • Backward compatible with previous versions.

Summary Table of the major differences between Bluetooth versions  (from 2.0 to 5.0).

 

REMEMBER:

Both Bluetooth and Bluetooth Low Energy operate on the same band (2,4GHz).

Both Bluetooth and Bluetooth Low Energy use the Master/Slave architecture: first you have to make the connection, than the communication can start.

BLE devices operate in Sleep Mode, so they wake up only if a connection request is sent, that allows them to have a longer duration than a Bluetooth Classic device.

BLE devices allow a faster connection and a more economic cost than a Bluetooth Classic device, but they have a lower data throughput and a lower reading distance.

 

POSSIBLE BLE-ORIENTED APPLICATIONS

Inside the IOT Industry (Internet Of Things), there are many applications in which the BLE technology can be integrated. Some example here below:

Indoor Position System -> Indoor tracking of a building with people/animals/objects in it (to know if the entity associated to the Beacon is in the area designed by the user).

Workplace Safety -> Constant monitoring of the workers and the possibility to send a special Advertising if something anomalous happens (e.g: fall, abandonment of the workstation etc…).

Access Control -> A beacon can replace the classic PVC card, but more permorming, there’s no need of a contact or to cross a gate, but only enter/leave a certain area determined by the user.

Marketing -> It’s possible to assign a Beacon to a certain category or product, and configure it with custom values, allowing the Beacon to send via Advertising a packet containing the relative data of the associated category/product.

Tourism -> Placing Beacons in different areas of a museum/park and associate them to a the desired areas/objects, so that it can describe them (Smart Guide).

Smart Home -> To Enable/Disable “smart” devices inside a house , based on certain values trasmitted by the Beacon (for example if a Beacon with a temperature sensor marks a value higher than 27°, send through ad hoc devices a command of POWER ON to an air conditioner). This type of applications don’t work only with a Master/Slave logic, but they need the support of ad hoc devices that can handle this type of dynamics.

 

CONCLUSIONS

The BLE technology is an excellent option for tracking and for long reading distance applications, by having a MAC ADDRESS that allows a global and unique identification. They can also be used alongside the RFID technology for many applications.

Here you can find our BLE Beacons: