Bluetooth Clock Synchronization via Timestamp Exchange
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Solution Overview
Problem
The Bluetooth protocol lacks a method for clock synchronization between connected devices, preventing them from sharing a common time reference and thus limiting the ability of one device to request specific actions from another at precise times.
Innovation Solution
A system and method where Bluetooth devices exchange packets containing timestamps to determine the offset between their internal clocks, allowing synchronization and enabling actions to be performed at specific times referenced to one device's clock, which is then converted to the other device's clock for accurate timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Bluetooth devices use connection intervals for communication timing, then communication synchronization is achieved, but clock synchronization between devices is not achieved
Solution Approach 1:
The patent applies preliminary action by having devices exchange timestamp information in advance through connection events. The central device sends a synchronization request packet containing its timestamp, and the peripheral device responds with its timestamp, allowing both devices to calculate clock offsets before actual synchronized operations begin. This preliminary timestamp exchange enables subsequent precise timing operations.
2Loss of time
If devices measure time between connection anchor points, then connection timing is maintained, but actual clock values of other devices remain unknown
Solution Approach 1:
The patent uses timestamps as an intermediary to transfer clock value information between devices. Instead of directly measuring or comparing clock values, each device includes its current timestamp in transmitted packets. The receiving device uses this timestamp intermediary to calculate the clock offset without needing to directly access or measure the other device's clock hardware.
3Ease of operation
If Bluetooth protocol provides connection timing, then communication structure is defined, but method to acquire clock synchronization information is missing
Solution Approach 1:
The patent makes the existing Bluetooth connection events multi-functional by having them serve both their original communication purpose and the additional function of clock synchronization. The same connection events that transmit data packets are also used to exchange timestamp information, eliminating the need for separate synchronization channels or protocols and reducing overall system complexity.
4Productivity
If central device requests actions at specific times, then timing control is needed, but without clock synchronization the timing cannot be coordinated
Solution Approach 1:
The patent implements feedback by having the peripheral device send its timestamp back to the central device in response to a synchronization request. The central device uses this feedback timestamp along with its own timestamp to calculate the clock offset. This feedback loop enables the central device to accurately determine timing relationships and issue precisely timed action requests.
Data Source
AI summary
A system and method of synchronizing the clocks between two connected Bluetooth devices is disclosed. The two devices exchange packets that contain a timestamp that is indicative of the time that each device received a packet from the other device. By exchanging this information, each device may determine the offset between its internal clock and the internal clock of the other device. Once clock synchronization is achieved, the central device may transmit packets to the peripheral requesting that particular actions be taken at specific times.