Введение
We are living in an increasingly wireless world. Each year, над 5 billion Bluetooth-enabled devices are produced and shipped globally. As a leading technology in wireless communication, Bluetooth’s innovations and continuously updated specifications are crucial across all industries. On September 3rd, the Bluetooth SIG (Special Interest Group) released the latest version of the Bluetooth specification – Bluetooth 6.0. The most significant update is the Bluetooth Channel Sounding technology, which enables precise distance awareness between Bluetooth devices. More updates include decision-based advertising filtering, advertiser monitoring, enhancements to the Isochronous Adaptation Layer (ISOAL), the LL extended feature set, and a frame space update. В этом блоге, we will delve into these new technologies and their future applications.
Updates in Bluetooth 6.0
Bluetooth Core Specification version 6.0 introduces several new features and enhancements, including Bluetooth Channel Sounding, decision-based advertising filtering, monitoring advertisers, improvements to the Isochronous Adaptation Layer (ISOAL), the LL extended feature set, and a frame space update. Let’s delve into each of these new features and enhancements in detail.
Bluetooth Channel Sounding
Bluetooth Channel Sounding is a new feature added in Bluetooth Core Specification version 6.0, enabling secure fine ranging between two Bluetooth devices with high security. Одним словом, Bluetooth Channel Sounding offers two key benefits for Bluetooth positioning: improved accuracy and enhanced security.
Back in 2019, Bluetooth got a major upgrade with the release of the 5.1 стандартный. This update introduced two new ways to pinpoint a device’s location — АОА (Angle of Arrival)and AoD (Угол вылета) — making Bluetooth location tracking much more precise. Bluetooth 5.1 AoA indoor positioning offers pinpoint accuracy of down to a few inches, revolutionizing applications such as asset tracking, внутренняя навигация, and smart home systems. Более того, the latest Bluetooth Channel Sounding technology offers two advanced distance measurement methods: PBR (Phase-Based Ranging) and RTT (Round-Trip Timing). These methods allow devices to determine their distance from each other with incredible accuracy, even when they’re far apart.
Точность: Bluetooth Channel Sounding uses PBR (Phase-Based Ranging) that can measure distances up to about 150 meters before encountering distance ambiguity. By combining RTT (Round-Trip Timing) with PBR, applications can detect and resolve this ambiguity, allowing for more accurate distance measurements over greater ranges.
Безопасность: Security concerns specific to distance measurement solutions typically involve the risk of an untrusted device deceiving a trusted device into believing that another trusted device is close enough to allow certain actions to be taken or authorized.
The combined use of PBR and RTT is one of Bluetooth Channel Sounding’s strategies to counter this threat. Since these two methods work completely differently, the likelihood of both being simultaneously attacked or manipulated to produce misleading results is extremely low. The high security offered by cross-checking PBR and RTT provides developers with greater possibilities.
Приложения: Bluetooth Channel Sounding comes with a range of advantages, but how does it improve our daily lives and business operations?
For the end-user of Bluetooth ‘Find My’ решения, which is the most ubiquitous low-power wireless technology, it would be easier and faster to locate lost items, whether in direction or distance. In digital key solutions, Bluetooth Channel Sounding can enhance security and user experience by ensuring a lock only opens when the authorized device is within a certain distance.
Bluetooth Channel Sounding offers exceptional technical flexibility in terms of security, точность, and latency. This gives developers maximum freedom to innovate, enabling the creation of endless possibilities between Bluetooth devices and paving the way for a more innovative, wireless world.
Decision-Based Advertising Filtering
Bluetooth defines two transmission types: data and advertising transmissions. In BLE(Bluetooth с низким энергопотреблением), there are a total of 40 physical channels, of which 3 are specifically dedicated to advertising. BLE supports related data packets being transmitted on both primary and secondary radio channels. Decision-based advertising filtering optimizes how devices handle incoming advertising data. This feature allows a scanning device to evaluate the relevance of data packets transmitted on the primary channel before receiving detailed data from the secondary channel. By doing so, the device can decide whether or not to receive data from the secondary channel, reducing the processing of irrelevant data. This significantly improves data processing efficiency and effectively lowers device power consumption.
Monitoring Advertisers
An advertiser is a device that broadcasts information to nearby devices using advertising packets. The host component of an observer device may instruct the Bluetooth LE controller to filter duplicate advertising packets, which means the host will only receive a single packet from each unique advertiser. This reduces the processing load on the host device, making it more efficient. Однако, it also means that the host won’t know if a device has moved out of range unless the observer device attempts to connect. This can cause the observer device to continue scanning unnecessarily when it’s supposed to connect with a device, leading to wasted energy. The monitoring advertiser feature helps to prevent this energy waste by informing the host when a device moves in and out of range.
ISOAL Enhancement
ISOAL (Isochronous Adaptation Layer) facilitates the transmission of real-time data like audio by bridging the gap between the upper layers (such as the Audio Profile) and the lower layers (such as the Link Layer) of the Bluetooth stack. ISOAL receives SDUs (service data units) from the upper layers and converts them into PDUs (protocol data units) to be sent over the Bluetooth link to the receiving device. There are two types of PDUs: framed PDUs and unframed PDUs.
The framed PDUs are encapsulated within frames, which are the physical units transmitted over the Bluetooth link. These frames contain header information such as the packet type, sequence number, error detection code, и более. While framed PDUs guarantee data integrity and sequencing, the header information for each data fragment can lead to latency. In Bluetooth 6.0, ISOAL introduces a new frame mode that reduces latency while maintaining data integrity. This improvement enhances the quality and smoothness of audio and video transmissions.
LL Extended Feature Set
The LL Extended Feature Set introduces a mechanism that allows Bluetooth devices to support a broader range of features beyond those specified in earlier Bluetooth standards. By offering 1984 support indication bits for future use, this extension ensures that Bluetooth technology can adapt to new applications and requirements as they arise.
Frame Space Update
Frame space refers to the time interval between sending two consecutive data packets at the link layer in Bluetooth. In Bluetooth 5.0 and later versions, frame space is referred to using the symbolic identifier T_IFS, with a fixed value of 150 µs. This fixed interval helps prevent data collisions and ensures smooth data transmission. Однако, Bluetooth 6.0 offers more flexibility, allowing frame space to be adjusted either shorter or longer.
A longer frame space value may benefit controllers with relatively low processing power, giving them more time to process longer data packets. A shorter frame space value can improve overall data throughput, which may be beneficial for applications such as:
- Sending the bulk data from a fitness tracker to a connected device like a smartphone or laptop in one go
- Firmware updates
- Sending BLE audio data packets faster to reduce the likelihood of collisions with other devices
Frame space updates enhance the flexibility of data transmission between Bluetooth devices, allowing them to perform better in complex environments.
Заключение
Bluetooth technology continues to evolve, increasingly integrated into our daily lives and industrial applications. Bluetooth Channel Sounding brings true distance awareness to devices, opening up possibilities for countless new applications. Decision-based advertising filtering will enhance data processing efficiency and reduce power consumption in BLE devices. Monitoring advertisers can make switching connections between devices quicker and more convenient, improving the user’s overall experience. Audio devices benefit significantly from advancements in ISOAL, while the LL extended feature set empowers Bluetooth devices with a broader range of features and updates. Frame space updates further enhance the user experience for both personal and BLE devices. The wireless Bluetooth world is becoming more precise, secure, diverse, and user-friendly.
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