Bluetooth Low Energy – Bluetooth LE or BLE for short – is a wireless technology for connecting devices such as smartphones, laptops and other smart devices within a limited radius. The standard differs from Bluetooth insofar as it is not designed for permanent data transfer but for the short-term exchange of small amounts of data.
The focal issue with Bluetooth LE is power consumption: conventional Bluetooth connections can quickly drain the power from a smartphone’s battery. Bluetooth Low Energy avoids this by exchanging small data packets at intervals, thus rendering a permanent connection between devices unnecessary. Thanks to the relatively short distance between transmitter and receiver, the signal strength can be used for triangulation for localisation systems, thus opening up further areas of application.
Bluetooth LE uses the same frequency range as conventional Bluetooth – 2.4 GHz in the licence-free ISM frequency band, as does Wi-Fi. With the emergence of the new Bluetooth 5 standard, the data rate (up to 2 MBit/s) or the range (with LE Long Range) can be adjusted by Bluetooth LE to suit the type of usage. This is leading to improvements and new fields of application, especially in connection with IoT.
Bluetooth LE for private users
Bluetooth LE experienced its greatest boom in the private sector with the emergence of wearables such as smart watches and fitness trackers, as more or less all smartphones can use Bluetooth LE. Thanks to the Internet of Things (IoT), even more devices with Bluetooth LE will make our everyday lives easier in future, whereby, along with WLAN, Bluetooth LE is one of the most used transmission standards for the IoT.
Bluetooth Low Energy is used for smart devices especially in cases when data does not have to be transmitted constantly or when a long battery life is of particular importance. This includes, for example, transmission of heart rate by the smart watch on a person’s wrist or transmission of the temperature in an apartment from the sensor to the heating’s control unit.
Bluetooth LE for commercial use
But Bluetooth LE not only holds interesting possibilities in store for private users; companies and public institutions can also benefit from this technology in many different ways. However, with regard to the commercial use of Bluetooth LE, the emphasis is on a different type of use from that for private users. The focus is not on the individual user but on connecting up large areas with the aid of Bluetooth beacons or locators. Once such a network has been set up, it can be used in various ways.
Indoor positioning systems (IPS) and real-time location systems (RTLS)
The greatest field of application is in indoor localisation systems, often referred to as indoor positioning systems (IPS) and real-time location systems (RTLS). There is no clear distinction between the two terms. As global positioning systems such as GPS cannot be used reliably within buildings, alternatives are required. Bluetooth LE is an obvious choice here.
A distinction must be made between two methods of positioning when deploying Bluetooth LE as an indoor localisation system. Although both methods are based on the measurement of the signal strength of the Bluetooth devices relative to one another (indicated in RSSI = Received Signal Strength Indicator), they differ in where the signals are processed. However, it is not impossible to deploy both positioning methods in parallel.
In distributed positioning, positions are calculated by endpoints such as smartphones. Bluetooth beacons are installed in a space and calibrated for this purpose. The beacons broadcast a Bluetooth signal at regular intervals, which is then processed by a receiving device such as a smartphone or tablet. With the aid of an app, the receiving device can then triangulate the position in the room in relation to the beacons from which it receives the signals.
The range and accuracy of localisation depend on the building layout. Newer beacons, such as those from Mist for example, can detect and compensate changes in the room or different endpoints thanks to artificial intelligence. Mist Beacons also feature the advantage that virtual beacons can be positioned using a Cloud application, thereby reducing the number of physical beacons.
This positioning method is particularly suitable for indoor navigation or tracking customers and guests with smartphones. This method merely requires Bluetooth to be activated on the receiving device, the user to be provided with an app and consent to be obtained by the user in order to comply with data protection regulations.
Centralised positioning is particularly suitable for tracking assets and people in a fixed environment such as warehouses, production facilities or hospitals. In this case, it is a server that calculates the position.
With this variant, we speak of locators rather than beacons. Like beacons, locators are also installed in precisely defined locations, but in this method of positioning they are connected to a central server. Access points from Cisco Meraki and Mist are also suitable for this method as both have a Cloud connection and provide tools for this type of tracking.
The object or person to be tracked is often equipped with a Bluetooth tag. This tag broadcasts a signal to the locator at regular intervals, depending on the expected rate of movement. The locator forwards all received signals to the server, where a locator engine calculates the position of the tags by means of triangulation. Thanks to an upgrade of the Bluetooth 5.1 specifications, it is now possible to capture direction data, which enhances the accuracy of positioning to within just a few centimetres.
In the commercial sector in particular, the various positioning methods open up new opportunities for interaction with the customer and allow enterprises a new view of their own resources. The many and varied ways of deploying Bluetooth LE are therefore the technology’s greatest strength. Moreover, modern access points, such as those from Cisco Meraki and Mist, not only enable deployment of both methods of positioning but also the possibility of combining WLAN and Bluetooth. It is the link up of these two technologies in particular that unlocks unforeseen and diverse deployment options for retail outlets, catering businesses and industry.