Clock Synchronization via Differential CSI for Precise Positioning
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Solution Overview
Problem
Existing network-based positioning systems face challenges in accurately and efficiently synchronizing clocks between nodes to estimate the position of a target device with high spatial resolution, particularly due to clock drift during synchronization processes.
Innovation Solution
A method for clock synchronization using differential channel-state information, where nodes synchronize their clocks retroactively after receiving a wireless signal from a target device, reducing clock drift by calculating time biases based on pre-calculated channel responses and partial channel-state information, thereby eliminating the need for iterative synchronization procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional iterative synchronization procedures are used, then clock synchronization can be achieved, but clock drift occurs during the synchronization process reducing accuracy
Solution Approach 1:
The system performs preliminary channel response calculations and stores them before actual synchronization is needed. When synchronization is required, the pre-calculated channel responses are retrieved and used to determine time biases, eliminating the need for iterative procedures during the actual synchronization event and thus preventing clock drift.
Solution Approach 2:
The invention creates a copy of the channel response data and stores it for later use. Instead of performing repeated measurements during synchronization, the system uses the stored copy of channel response information to rapidly determine time biases, reducing synchronization time and minimizing clock drift effects.
2Reliability
If iterative synchronization procedures are used, then clock synchronization can be achieved, but the process requires significant time and resources
Solution Approach 1:
Channel responses are pre-calculated and stored in advance, so when synchronization is needed, the system can quickly retrieve and use this pre-computed information without performing iterative procedures, significantly improving synchronization efficiency while maintaining reliability.
Solution Approach 2:
The invention extracts and stores the essential channel response information separately from the main processing flow. This extracted data can be rapidly accessed during synchronization events without requiring the full iterative synchronization procedure, improving productivity while maintaining synchronization reliability.
3Measurement precision
If clocks are synchronized in advance, then positioning can be performed, but clock drift during the positioning process reduces spatial resolution
Solution Approach 1:
The system uses stored copies of channel response data to rapidly determine time biases at the moment of positioning events. This allows the system to maintain high spatial resolution by using pre-stored information rather than performing time-consuming iterative procedures that would allow clock drift to degrade accuracy.
Data Source
AI summary
A method includes: based on a synchronization signal transmitted from a master node and received at a sniffer node, recording a partial channel-state information characterizing a communication channel between the master node and the sniffer node for a second time period; in response to a localization signal transmitted from a target device, calculating a time bias between the master node and the sniffer node based on a transmit time of the synchronization signal, a third receive time of the synchronization signal at the sniffer node, a channel response characterizing the communication channel for a first time period, and the partial channel-state information; and estimating a position of the target device based on a first receive time of the localization signal at the master node, a second receive time of the localization signal at the sniffer node, and the time bias.