Learn more about Bluetooth Low Energy (BLE) and how this flexible, efficient, and omnipresent radio-frequency technology can be used to detect location and power a multitude of indoor positioning and location-based IoT applications.
Bluetooth Low Energy, or BLE, is a radio-frequency (RF) technology for wireless communication that can be leveraged to detect and track the location of people, devices, and assets for many indoor positioning use cases - including asset tracking, indoor navigation, proximity services and more. Incredibly widespread and accessible, Bluetooth is a technology prevalent throughout indoor spaces and supported by so many of today’s devices. Like other communication protocols including Wi-Fi and UWB, BLE can be used to transmit data between devices using radio waves.
Released in 2010, BLE 4.0 was the successor to the previous generation versions of Bluetooth Classic, and was created to consume very low power, significantly less than that of Bluetooth Classic versions and other RF standards. This energy-efficient design set the stage for the emergence of new Bluetooth technologies, including further integration into smartphones and other wireless devices, the development of wearables and various IoT devices, and the adoption of battery-powered BLE beacons.
The growth of BLE technology brought fundamental change to the global Bluetooth ecosystem. A whole suite of Bluetooth-enabled devices entered indoor spaces, many of which now represent the over 8 billion Bluetooth devices worldwide. New Bluetooth compatible infrastructures and tools unlocked innovative location-aware capabilities.
Many new BLE technologies emerged following the 2013 release of the world’s first beacon communication protocol, Apple’s iBeacon. iBeacon made it possible for physical beacons to communicate with wireless devices in close proximity, working with both iOS and Android applications. In 2015, Google launched their beacon protocol, Eddystone, designed with openness and interoperability in mind. These two leading beacon protocols and the many physical beacon offerings they are used with, along with the utilization of other BLE technologies such as location tracking sensors and tags, have enabled a wide array of indoor positioning and location services applications, transforming the way people and devices can interact with indoor spaces.
These technologies and the overall Bluetooth communication protocol, are seeing continued advancement. In 2016, a new version of Bluetooth was introduced, Bluetooth 5.0. Building on BLE 4.0, this new version allows for communication over higher data rates and longer ranges. Announced in 2019, the Bluetooth 5.1 release is poised to bring enhanced abilities that will lead to more precise location detection via direction finding (DF), which can deliver centimeter level accuracy.
BLE has unique characteristics that have made it one of the most popular RF technologies for indoor positioning. BLE has a large presence in wireless devices, an extensive set of low-power, low-cost, and easy to implement hardware options, and the flexibility to be used in many location-based applications.
BLE beacons are small, versatile, and low-power Bluetooth transmitters that can be detected by wireless devices like BLE-enabled smartphones. Beacons can be deployed in fixed positions, such as mounted on walls or structures, or placed on mobile assets, to provide location references for indoor positioning applications. This supports bring-your-own-device (BYOD) concepts, allowing anyone to interact with a BLE-enabled application using their smartphone or other embedded devices. BLE beacons can be used to find a device’s location and deliver relevant content, such as documents, videos, apps, and more, or offer guidance concerning the time or location of the user, keeping users informed and engaged.
Beacons broadcast signals on regular intervals that can be detected by other BLE-enabled devices. Location data from the beacons is collected by a BLE device and forwarded to the IPS to determine the device’s location. This can support various location-aware applications and even trigger specific actions.
Beacons come in all shapes and sizes. Many beacons have long-lasting internal batteries that operate over multiple years, or can be powered via a connection like USB. BLE technology is typically cheaper to produce than other RF technologies, resulting in small, low-cost, low-maintenance hardware options that can be tailored for deployments that fit your unique needs. Some beacons go beyond BLE and incorporate additional technologies such as accelerometers or temperature sensors for enhanced results.
Virtual beacons allow organizations to add BLE beacon technology without the need for much extra hardware. With virtual Bluetooth beacons, antennas can be added to compatible Wi-Fi Access Points, and leveraged with additional software tools for various indoor positioning applications.
Many common enterprise-grade Wi-Fi access points now come equipped with BLE technology built-in. This allows organizations to use access points as both beacons and sensors that can detect and locate transmitting BLE devices, without having to establish a secondary set of infrastructure.
BLE indoor positioning solutions use either BLE-enabled sensors or beacons to detect and locate transmitting Bluetooth devices, such as smartphones or tracking tags throughout indoor spaces. Location data collected by the sensors or sent from beacons to mobile devices is then ingested by various locationing applications and translated into insights that power multiple location-aware use cases.
BLE positioning with sensors utilizes BLE-enabled sensors that are deployed in fixed positions throughout an indoor space. These sensors passively detect and locate transmissions from BLE smartphones, asset tracking tags, beacons, personnel badges, wearables and other Bluetooth devices based on the received signal strength of the transmitting device. This location data is then sent to the central indoor positioning system (IPS) or real-time location system (RTLS). The location engine analyzes the data and uses multilateration algorithms to determine the location of the transmitting device. Those coordinates can be used to visualize the location of a device or asset on an indoor map of your space or leveraged for other uses depending on the specific location-aware application.
BLE beacons repeatedly pulse out BLE signals. These signals can be detected by surrounding devices, including smartphones and BLE-enabled sensors. Deployed in fixed positions throughout an indoor space, the signal continuously broadcasted by the beacon contains its unique identifier. This identifying code is sent out periodically, along with other data, depending on the beacon communication protocol being used.
A smartphone or other wireless device that is enabled with a dedicated app or pre-configured service, when in range of the beacon, will receive and analyze the signal from the beacon in a user-centric approach or send this information to a server in a server-centric approach. The detection between one beacon and a device can enable proximity-based location services that determine whether a beacon and device are in range of each other. With multiple beacons strategically placed throughout an indoor space, communication between three or more beacons and a wireless device can be used to position the device via RSSI multilateration. Depending on the application, the determined location of the device can trigger a specific action or be leveraged for a variety of applications or services.
BLE beacons can also be deployed on mobile objects and detected and located by fixed BLE-enabled sensors, which can be useful in asset tracking scenarios.
BLE indoor positioning and real-time location systems can yield different levels of accuracy depending on the system architecture, hardware selections, and density of deployed sensors or beacons. Both indoor positioning using BLE sensors or beacons can deliver location accuracy typically below 5 meters (with optimal conditions and deployment).
Bluetooth, similar to Wi-Fi technologies, typically rely on signal strength (RSSI) to estimate the locations of devices. This method of determining location typically yields positional accuracy in the meter level and is much less precise than a technology like UWB, which uses Time of Flight (ToF) distance-based measurement for very precise centimeter-level accuracy. While BLE isn’t currently the most accurate RF technology for indoor positioning, it’s still highly effective and one of the most widely used. Many indoor positioning use cases don’t require a high degree of precision, making BLE a suitable option that offers many unique advantages including flexibility, low-power and cost, and ease of implementation.
The release of Bluetooth 5.1, and its new direction-finding features, will make it possible for BLE to determine location with accuracy in the sub-meter level. This is due to the new ability to calculate the direction of a Bluetooth signal via Angle of Arrival (AoA), which will be used along with detected signal strength (RSSI) to determine and track the location of devices and assets and deliver enhanced precision. To be able to find direction, a mobile asset, such as a tag or beacon, with a single antenna transmits to a fixed BLE sensor with a multi-antenna array. The phase shift of the multiple antennas, as a result of receiving the signal, is measured to determine the angle of approach of the transmitting mobile device. Combined with RSSI, the AoA is used to generate device coordinates to centimeter-level accuracy.
The range of BLE positioning can differ depending on factors such as whether you are using BLE beacons or BLE-enabled sensors or the nature of the indoor space. BLE generally operates over a shorter range than other RF technologies, such as UWB or Wi-Fi, operating best within 0-25 meters and up to 100 meters (with optimal conditions and deployment).
Bluetooth, like other RF standards, offers unique characteristics and advantages that may make it a suitable option, depending on individual needs, budget, facility, and specific location-based use cases. The most critical differences between BLE and other technologies, is its lower power consumption and flexibility in many location-aware applications. BLE is present in devices throughout indoor spaces, leveraged by many location tracking systems, and can be extended for indoor positioning across a whole suite of industries and use cases.
