Differential Channel State Clock Sync for Wireless Positioning
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Solution Overview
Problem
Existing network-based positioning systems face challenges in accurately and efficiently synchronizing clocks between nodes to improve position estimation accuracy, particularly due to clock drift during synchronization processes.
Innovation Solution
A method for clock synchronization using differential channel state information, where nodes synchronize 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 iterative synchronization procedures are used to synchronize clocks between nodes, then clock synchronization accuracy is improved, but synchronization latency increases and productivity decreases
Solution Approach 1:
The system performs channel response calculation in advance before synchronization is needed. The master node calculates the channel response between itself and each slave node during normal operation, storing this information for later use in time bias calculation, thereby avoiding the need for iterative synchronization procedures when actual synchronization is required
Solution Approach 2:
The patent replaces the mechanical iterative synchronization process with a direct calculation method using pre-calculated channel responses. Instead of repeatedly adjusting and measuring clock offsets through multiple iterations, the system directly computes time biases using the stored channel response information and partial channel state information from synchronization signals
2Measurement precision
If iterative synchronization procedures are used to synchronize clocks between nodes, then clock synchronization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential synchronization information (time bias) directly from the synchronization signal using pre-calculated channel responses. By taking out only the necessary time offset information through direct calculation rather than requiring the full iterative synchronization protocol, the system reduces procedural complexity while maintaining accuracy
Solution Approach 2:
The system uses the pre-calculated channel response as a copy or reference that can be directly applied to calculate time biases. Instead of re-performing complex synchronization measurements, the system copies the channel characteristics from the pre-calculated response and uses them to determine timing offsets
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.