Bluetooth 6.0 specs add centimeter-level accuracy device tracking, improved device pairing

The Bluetooth Special Interest Group (Bluetooth SIG) has just released version 6.0 of the Bluetooth standard, and with it, come some upgrades since the last major version -- Bluetooth 5.0 -- launched all the way back in 2016.

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The new Bluetooth 6.0 standard has two new features that assist in reducing power consumption: Decision-Based Advertising Filtering and Monitoring Advertisers. These new features help the upgraded Bluetooth 6.0 devices reduce power consumption, and increase efficiency making sure that they're only scanning for data packets when they receive data on their primary channel, relevant to their application.

Bluetooth 6.0 is also capable of telling devices when another device they want wants to connect to, moves out of range, so that they can cancel their attempts of making a connection and conserve energy. Another big feature is Bluetooth Channel Sounding, a new technology that provides two upgrades to Bluetooth devices: enhanced security, and improved accuracy in location finding.

Bluetooth Channel Sounding improves security by allowing Bluetooth 6.0 devices to communicate wirelessly to find each other's locations accurately, which makes it harder to spoof the Bluetooth signal and manipulate its strength. Why is this important?

The Bluetooth SIG says that Bluetooth Channel Sounding will deliver "centimeter-level accuracy over considerable distances". This is great for Android Find My Device network and Apple's Find My service, but Apple still uses Ultrawide Band (UWB) chips for accurate directions. However, with Bluetooth 6 and its new Bluetooth Channel Sounding, devices could provide their exact location to authorized devices, all without a UWB chip.

What's New in Version 6.0

This article highlights the new features and feature enhancements developers can expect to take advantage of when building with the new version of the Bluetooth Core Specification.

• Bluetooth® Channel Sounding: This innovation brings true distance awareness, introducing transformative benefits across various applications. The user experience of Find My solutions can be greatly improved, making it easier and faster to locate lost items. In digital key solutions, Bluetooth® Channel Sounding will add a robust layer of security, ensuring that only authorized users within a specified range can unlock doors or access secure areas. And, by infusing billions of everyday devices with true distance awareness, Bluetooth® Channel Sounding unlocks a world of possibilities for developers, freeing them to imagine and create innovative experiences that will continue to enhance our connection with our devices, one another, and the world around us.
• Decision-Based Advertising Filtering: The Bluetooth Low Energy (LE) Extended Advertising feature supports a series of related packets being transmitted on both primary and secondary radio channels. Decision-based advertising filtering allows a scanning device to use the content of a packet received on a primary advertising channel to decide if it should scan for related packets on the secondary channels, improving scanning efficiency by reducing the time spent scanning on secondary channels for packets that might not contain PDUs relevant to the application.
• Monitoring Advertisers: The host component of an observer device may instruct the Bluetooth LE controller to filter duplicate advertising packets. When filtering of this type is active, the host will only receive a single advertising packet from each unique device (subject to Bluetooth Core Specification definitions of what constitutes a unique device in this context). This improves efficiency for the host but has the disadvantage that the host has no way of knowing whether a device is still within range when circumstances dictate that the observer device should now attempt to connect to it. This can lead to the observer wasting energy performing high-duty cycle scanning for a previously discovered device that is no longer in range. The new monitoring advertisers feature uses Host Controller Interface (HCI) events to inform the host whenever a device of interest moves in and out of range.
• ISOAL Enhancement: The Isochronous Adaptation Layer (ISOAL) makes it possible for larger data frames to be transmitted in smaller link-layer packets and ensures the associated timing information that is needed for the correct processing of the data by receivers can be reconstituted. ISOAL can produce either framed or unframed PDUs depending on certain variables. If framed PDUs are produced, latency can be increased as a result. In Bluetooth Core Specification version 6.0, ISOAL has been improved by defining a new framing mode that reduces latency for use cases that are particularly sensitive to this issue. The same feature also improves reliability.
• LL Extended Feature Set: With this advancement, devices can exchange information about the link-layer features that they each support. This capability has been enhanced to support larger numbers of features, which has become necessary as the sophistication and versatility of Bluetooth LE have grown.
• Frame Space Update: Prior versions of the Bluetooth Core Specification defined a constant value for the time that separates adjacent transmissions of packets in a connection event or connected isochronous stream (CIS) subevent. The value is designated T_IFS in the specification and had a fixed value of 150 µs. In version 6.0 of the Bluetooth Core Specification, frame spacing, as used in connections or with connected isochronous streams, is now negotiable and may be shorter or longer than 150 µs.