Partial TSF Synchronization in Fine Timing Measurement
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Solution Overview
Problem
In wireless communication systems, precisely synchronizing local clocks among multiple stations is challenging, especially in scenarios where stations are in power-saving mode for extended periods, leading to inefficiencies and high power consumption due to constant synchronization methods.
Innovation Solution
Embedding partial timing synchronization function (TSF) timer values in fine timing measurement (FTM) frames allows wireless devices to set their local TSF timers based on received values, enabling efficient synchronization without constant Beacon or probe response reliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If constant Beacon or probe response methods are used for synchronization, then timing synchronization accuracy is maintained, but power consumption increases and efficiency decreases
Solution Approach 1:
The patent implements periodic synchronization updates instead of constant synchronization. Stations perform timing synchronization at specific intervals using FTM frames rather than continuously monitoring Beacons or probe responses. This periodic approach maintains acceptable synchronization accuracy while significantly reducing power consumption during extended power-saving periods.
Solution Approach 2:
The patent performs timing synchronization in advance before stations enter power-saving mode. By embedding partial TSF timer values in FTM frames and synchronizing beforehand, stations can remain in low-power state for extended periods while still maintaining adequate timing alignment, avoiding the need for continuous synchronization during sleep periods.
2Measurement precision
If stations remain in active mode for constant synchronization, then timing accuracy is maintained, but power consumption increases
Solution Approach 1:
The system transitions from continuous synchronization requiring constant active mode to periodic synchronization using FTM frames. Stations can enter power-saving mode between FTM exchanges, activating only briefly to receive synchronization updates and then returning to low-power state, significantly reducing overall power consumption while maintaining clock accuracy.
Solution Approach 2:
Stations use their own local clocks combined with received partial TSF timer values from FTM frames to autonomously maintain synchronization. This self-service approach eliminates the need for continuous external synchronization signals, allowing stations to operate independently in power-saving mode while maintaining adequate timing alignment.
3Measurement precision
If full TSF timer values are transmitted frequently, then synchronization accuracy is improved, but communication overhead and complexity increase
Solution Approach 1:
The patent extracts only the necessary partial TSF timer values from the full 64-bit timestamp and transmits them in FTM frames. This extraction approach provides sufficient synchronization information for most applications while significantly reducing the data transmission burden and protocol complexity compared to transmitting complete high-resolution timestamps frequently.
Solution Approach 2:
The system uses partial TSF timer values rather than complete timestamps, applying partial action principle. This provides adequate synchronization for typical use cases without the overhead of full precision timing data, balancing synchronization quality with communication efficiency and reducing protocol complexity.
Data Source
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AI summary
Disclosed herein are techniques for timing synchronization between a first wireless device and a second wireless device. The techniques include sending a first message by the first wireless device to the second wireless device, obtaining a first timestamp at the first wireless device by the first wireless device, and receiving, by the first wireless device, a fine timing measurement frame from the second wireless device in response to the first message. The fine timing measurement frame includes at least a part of a second timestamp from the second wireless device. The techniques further include determining by the first wireless device that the first wireless device is not synchronized to the second wireless device based at least partially on the part of the second timestamp and the first timestamp.