Technology
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10 Apr 2025
Bluetooth is a short range wireless technology that operates in the unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz radio frequency band.
The Bluetooth Special Interest Group (SIG) manages its specifications, which provide the foundation for interoperability among all devices. The Bluetooth SIG regularly updates these specifications with new features to improve performance and enable new use cases. u-blox is a member of the Bluetooth SIG.
Overview of key features per Bluetooth® Core Specification
The number of Bluetooth enabled devices shipped each year exceeds five billion. In fact, Bluetooth has become the standard for wireless connectivity between mobile devices, and it’s now available in all smartphones and tablets. Hundreds of smartphone applications and custom handheld controllers manage or monitor other systems via Bluetooth technology, which also enables the sharing of media, files, and information among users.
Bluetooth frequency dynamically adjusts its hopping sequence through Adaptive Frequency Hopping (AFH) to avoid channels that may be in use by other technologies. Automatic power control reduces the output power to levels required to maintain connections while not interfering with other nearby 2.4 GHz radios (including other Bluetooth connections). Forward Error Correction (FEC), available for Bluetooth Long Range and some Bluetooth Classic packet types, allows receivers to correct limited bit errors introduced in harsh environments. As a result, Bluetooth is ideal for industrial, automotive, and medical applications where robustness is crucial.
Bluetooth wireless technology currently comes in two variants: Bluetooth Classic, also known as BR/EDR (Basic Rate/Enhanced Data Rate), for audio and streaming applications, and Bluetooth LE (Low Energy), which targets battery-operated devices for intermittent data transmission. The latter variant has enabled rapid ecosystem growth with more device types and use cases that significantly extend the battery life of IoT devices and wearables.
Bluetooth Classic is designed for audio connections and streaming applications. Bluetooth LE technology, on the other hand, is ideal for applications that periodically transfer small amounts of data and require ultra-low power consumption. It uses a much faster connection mechanism than Bluetooth Classic, which means that the radio can be on for very short periods of time. This makes it particularly useful for sensors in Internet of Things (IoT) applications.
Dual-mode Bluetooth devices support both Bluetooth LE and Bluetooth Classic. For instance, a smartphone can use Bluetooth Classic to connect to a laptop and Bluetooth LE to connect to a heart rate sensor. The heart rate sensor, however, uses only Bluetooth LE and is an example of a single-mode Bluetooth LE device.
In Bluetooth LE, devices have central and peripheral roles. Once connected, devices form a central and peripheral topology similar to Bluetooth Classic. In the example above, the heart rate sensor acts as a peripheral while the smartphone acts as central.
A profile is a specification describing particular use cases to achieve interoperability between devices that support the same profile. Two Bluetooth Classic-enabled devices must implement the same profile in order to be connected. For instance, Personal Area Networking (PAN) allows two or more devices to form an ad hoc network, and the Serial Port Profile (SPP) replaces a serial communication interface.
In Bluetooth LE, the Generic Attribute (GATT) profiles define a hierarchical data structure used to exchange configuration data between Bluetooth LE devices. The GATT profiles describe use cases, while the GATT services are characteristics (data, descriptions, possible actions, etc.) that define the capabilities of a Bluetooth LE device.
GATT defines clients (devices that “want” data) and servers (devices “with” data). The client and server exchange information to establish a dialog and define the payload transport requirements and their repetition rates or event triggers.
Both functions can reside in the same product: our u blox Bluetooth LE modules have both GATT server and GATT client roles, a design that provides flexibility. It is also possible to define custom services. For instance, we have defined the u-blox Serial Port Service for reliable serial data exchange between Bluetooth LE devices, similar to the Bluetooth Classic SPP.
Bluetooth Core 5.0 includes three major enhancements to Bluetooth LE: increased data rate (2x the speed), extended Bluetooth range (4x the distance), and enhanced advertising capability. The increased data rate and enhanced advertising capability simply require a software upgrade, while the extended range requires new hardware.
Bluetooth mesh enables many to many network topologies using Bluetooth LE solutions. Bluetooth Mesh Networking is available as a software update to Bluetooth LE and is compatible with any Bluetooth LE version (from Bluetooth® Core 4.0 and above).
Bluetooth Mesh Networking extends the coverage area by allowing nodes to forward messages, acting as relays in a cooperative network. This opens the door to new applications, including industrial sensor networks, building automation, street lighting, environmental monitoring, and many other use cases.
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The most important addition in Bluetooth Core 5.1 is Direction Finding. With this feature, proximity and positioning systems can deliver sub-meter accuracy, enabling exciting new use cases such as indoor positioning, wayfinding, asset tracking, and point-of-interest information solutions.
Technically, this is done by determining the angle or direction of a transmitted or received signal using one of two defined methods. A positioning engine combines angle measurements from multiple anchor points to calculate a high precision position.
Direction Finding enables higher indoor positioning accuracy than the traditional approach that relies on beacons and RSSI values.
Watch how we integrated Direction Finding into our Bluetooth indoor positioning solution
Bluetooth Core 5.2 introduces Isochronous Channels that primarily support LE Audio, the next generation of Bluetooth audio. This feature enables several use cases, such as music sharing, hearing aid systems, and multilingual audio systems. It is also applicable to a variety of industrial applications, where sending time-synchronized data to multiple devices is essential.
The new LE Power Control feature enables Bluetooth devices to dynamically optimize the transmission power used to communicate between connected devices. This improves overall system performance and reduces power consumption.
Finally, the Enhanced Attribute Protocol - EATT - supports concurrent transactions, aiming to reduce end-to-end latency of one or more applications and improve responsiveness for a better user experience.
Bluetooth Core 5.3 includes the following feature enhancements:
Periodic Advertising Enhancement. Bluetooth transmitting devices will typically transmit the same information multiple times to ensure reception. With this enhancement, received data is scanned only once and duplicates are discarded immediately.
Host to Controller Encryption Key Size Control Enhancements allow the host to specify a minimum key size, enabling the possibility to specify whether the device should use longer encryption keys or faster encryption algorithms.
LE Connection Sub-Rating enables quick switching between low- and high-duty cycles. Some product types spend much of their time in a low-duty cycle connection mode to conserve power. When a particular application requires a higher bandwidth, connection parameters must change as quickly as possible.
LE Channel Classification Enhancement enables peripheral Bluetooth devices to perform channel classification, thereby improving throughput and reliability.
Bluetooth Core 5.4 includes the following enhancements:
Periodic Advertising with Responses (PAwR) enables the bidirectional transfer of application data between a single central device and many other devices in a star network topology.
Encrypted Advertising Data introduces a standardized way to encrypt data in advertising by providing a new Advertising Data (AD) type called Encrypted Data. This carries a sequence of one or more encrypted AD types.
LE GATT Security Levels Characteristic indicates to devices the security mode and level required to access all GATT server features. It is intended to limit disruptions to the user experience caused by security conditions that may delay access to an attribute.
Advertising Coding Selection enables hosts to specify the value of the S-coding parameter for LE Coded PHY to be used with extended advertising.
Bluetooth Core 6.0 introduces major advancements in precision tracking, data throughput, and responsiveness. Key features include:
The Bluetooth SIG is constantly working to improve its technology and explore new features:
| Version/extension | Features | Description |
|---|---|---|
| Bluetooth Core 4.1 | BR/EDR Secure Connections | Offers 128-bit AES encryption strength |
| LE Dual-Mode Topology | Enables devices to act as dual-mode Bluetooth hub and Bluetooth LE peripheral simultaneously | |
| LE L2CAP Dedicated Channels | Enables IPv6 over Bluetooth LE | |
| Bluetooth Core 4.2 | LE Secure Connections | Provides 128-bit AES encryption strength for Bluetooth LE |
| LE Data Packet Length Extension | Up to 2.5x increase in data throughput | |
| Bluetooth Core 5.0 | LE 2M | Expands the data rates supported by Bluetooth LE up to 2 Mbps, doubling the speed |
| LE Coded (long range) | Extends the range supported by Bluetooth LE devices to four times the range | |
| LE Advertising Extension | Supports longer advertisement messages for more feature-rich Bluetooth beacons | |
| Bluetooth Core 5.1 | Direction Finding | Enhances indoor positioning, asset tracking, proximity applications, and indoor navigation |
| Bluetooth Core 5.2 | Isochronous Channels | Enable audio streaming and synchronized data transfer via Bluetooth LE |
| LE Power Control | Allows dynamic power optimization via Bluetooth LE | |
| Enhanced Attribute Protocol | Supports concurrent transactions aimed at reducing the end-to-end latency of one or more applications and improve user experience in terms of responsiveness | |
| Bluetooth Core 5.3 | Periodic Advertising Enhancement | Received data requires only one examination, with duplicates deleted instantly |
| Host to Controller Encryption Key Size Control Enhancements | Ability to specify whether the device should use longer keys or faster encryption algorithms | |
| LE Connection Sub-Rating | Enables fast switching between low and heavy-duty cycles | |
| LE Channel Classification Enhancement | Enables channel classification from Bluetooth peripheral devices | |
| Bluetooth Core 5.4 | Encrypted Advertising Data | Provides new advertising data (AD) called Encrypted Data, which carries a sequence of one or more encrypted AD types |
| Periodic Advertising with Responses (PAwR) | Enables bidirectional transfer of application data between a single central device and other devices in a star network topology. | |
| LE GATT Security Levels Characteristic | Devices can specify the security mode and level needed to access all GATT server features. | |
| Advertising Coding Selection | Enables specifying the value of the S-coding parameter for LE Coded PHY, which is required for extended advertising | |
| Bluetooth Core 6.0 | Channel Sounding | For high accuracy distance measurements (HADMs) between two Bluetooth LE devices using two methods called Phase-Based Ranging (PBR) and Round-Trip Time (RTT) |
| Future features* | Higher Data Throughput | Delivers higher data rates (up to 8 Mbps) to support the streaming needs of larger media |
| Ultra-low latency HID | Provides polling rates as high as 1000 Hz to compete with USB-wired or proprietary wireless communications | |
| Higher Frequency Bands | Help ensure that new Bluetooth performance enhancements come with new spectrum extensions and continue with the new release well into the future |
*Feature still being defined/discussed by the Bluetooth SIG working group
Bluetooth is a short range technology with endless applications across industrial, smart home, medical, and automotive markets. For example:
Bluetooth LE with Angle-of-Arrival (AoA) enables you to track the location of medical equipment, medications, staff, and even patients. It helps you reduce asset search time and redundant equipment inventory, understand where and when critical medical equipment is being used, and limit patient roaming or access to restricted areas.
Bluetooth LE sensors collect data while in use, enabling real-time monitoring based on lifecycle characteristics to notify technicians of abnormal behavior/response or earlier service needs, preventing unexpected failures that could lead to potential production downtime.
The collected data can be used for analytics, process optimization, predictive maintenance or energy efficiency improvements.
Bluetooth LE Audio for automotive is the next generation of Bluetooth audio, allowing users to share music with multiple Bluetooth speakers or headsets, so friends and family can share the same experiences and personalize the audio experience in a smoother way.
u-blox is committed to delivering cutting-edge products while continuously updating its portfolio through firmware updates. To learn how to upgrade u-blox modules to the latest Bluetooth versions, visit our product resources page.
In addition, Bluetooth can be combined with other technologies such as Wi-Fi, GNSS, LTE/5G, and Zigbee to create more integrated and efficient systems. Multiple radio communication devices incorporating these wireless technologies can switch between them to optimize connectivity and functionality based on needs and environmental factors.
For more information on u-blox’s offerings, explore the full u-blox Bluetooth portfolio.
Stand-alone Bluetooth® LE module
Stand-alone Bluetooth LE modules
Stand-alone Bluetooth 5.1 low energy modules
Stand-alone Bluetooth 5 low energy modules
Stand-alone Wi-Fi 6 multiradio modules
Stand-alone Bluetooth 5.1 Low Energy module
Host-based Wi-Fi 6/6E and Bluetooth 6.0 modules for the IoT
Stand-alone Bluetooth 5.1 low energy modules
Stand-alone Wi-Fi™ 6 multiradio modules
Host-based compact automotive modules
Host-based flexible automotive modules
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