Wireless PPS Synchronization for Indoor Sub-Microsecond Timing
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Solution Overview
Problem
Existing wireless devices face challenges in achieving precise time synchronization, especially in indoor environments where GNSS signals are unavailable, and implementing the 1588 protocol is costly and limits accuracy to 10 microseconds, which is inadequate for Wi-Fi 7 and Time Sensitive Network applications.
Innovation Solution
A host wireless device generates a modulated PPS signal using a sine wave and transmits it to a client device, which demodulates and compensates for delays to achieve sub-microsecond accuracy without requiring GNSS or 1588 protocol support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS receivers are used for time synchronization, then time accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual PPS signal by copying the timing characteristics of a physical PPS signal through software processing. The system captures Wi-Fi beacon frames containing timing information and generates synthetic PPS signals that replicate the precision of hardware-generated signals without requiring expensive GNSS receivers or dedicated PPS hardware circuits.
Solution Approach 2:
The patent replaces mechanical/hardware-based time synchronization systems (GNSS receivers, dedicated PPS hardware) with a software-based solution. By using software to process Wi-Fi beacon frames and generate virtual PPS signals, the system eliminates the need for complex hardware components while maintaining time synchronization accuracy.
2Measurement precision
If 1588 protocol is implemented for time synchronization, then network-wide synchronization is improved, but cost increases and accuracy is limited to 10 microseconds
Solution Approach 1:
The patent uses readily available, low-cost Wi-Fi beacon frames as the basis for time synchronization instead of expensive 1588 protocol infrastructure. The system extracts timing information from standard Wi-Fi beacons that are already present in the network, eliminating the need for costly 1588 protocol support in all devices while achieving sub-microsecond accuracy.
Solution Approach 2:
The patent changes the fundamental parameter of time measurement from microsecond-level 1588 protocol timestamps to nanosecond-level Wi-Fi beacon timing. By processing the precise timing information embedded in Wi-Fi beacon frames and generating virtual PPS signals, the system achieves 1000x better accuracy (sub-microsecond vs. 10 microseconds) without increasing implementation cost.
3Adaptability or versatility
If indoor deployment without GNSS is used, then adaptability is improved, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent introduces virtual PPS signals as an intermediary that bridges the gap between available Wi-Fi beacon information and precise time synchronization requirements. These virtual PPS signals act as a mediator that translates standard Wi-Fi timing data into high-precision time references, enabling accurate synchronization in indoor environments where direct GNSS signals are unavailable.
Solution Approach 2:
The patent creates virtual copies of PPS signals using software processing of Wi-Fi beacon frames. By copying the timing characteristics of beacon frames and generating synthetic PPS signals, the system maintains time synchronization accuracy in indoor environments without requiring physical PPS hardware or GNSS reception capability.
Data Source
AI summary
A method for time synchronization for wireless device. The method comprises receiving a modulated signal from a second wireless device, the modulated signal indicating information of a first PPS signal for time synchronization, and the first PPS signal being received by the second wireless device via a network protocol for time synchronization or a GNSS receiver. The method further comprises obtaining a second PPS signal by demodulating the received modulated signal. The method further comprises determining a delay offset between the first PPS signal and the second PPS signal. Furthermore, the method further comprises recovering the first PPS signal for time synchronization based on the second PPS signal and the delay offset. In this manner, the accuracy of the time synchronization can be improved, and the cost for the entire network can be reduced.