Wireless Frame Synchronization Circuit for Sub-Sample Timing Accuracy
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Solution Overview
Problem
Existing frame synchronization detection methods in wireless networks, such as Bluetooth and Bluetooth Low Energy, lack accuracy in timing estimation, particularly in fractional timing, which affects distance estimation and security applications.
Innovation Solution
Implementing a frame synchronization detection system with fractional approximation using a correlation circuit and a fractional timing approximation circuit to enhance timing accuracy by identifying frame synchronization patterns and determining pulse shapes for more precise correlation peak values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional frame synchronization detection methods are used, then the system complexity remains low, but the timing estimation accuracy is insufficient
Solution Approach 1:
The patent segments the timing estimation process into two distinct stages: integer timing estimation using conventional correlation methods, and fractional timing estimation using a separate fractional timing estimator. This segmentation allows each estimator to be optimized for its specific purpose, improving overall accuracy without requiring a complete redesign of the synchronization system.
Solution Approach 2:
The patent introduces a fractional timing estimator as an intermediary component between the conventional correlation detector and the final timing decision. This intermediary refines the timing estimate by analyzing fractional sample positions, thereby improving measurement precision without directly modifying the core correlation detection mechanism.
2Measurement precision
If fractional timing approximation is implemented, then the round trip time estimation accuracy improves, but the computational complexity increases
Solution Approach 1:
The patent performs preliminary integer timing estimation using conventional correlation methods before applying the more computationally intensive fractional timing approximation. By first establishing a coarse timing estimate, the system narrows the search space for fractional estimation, reducing the overall computational burden while maintaining high accuracy.
Solution Approach 2:
The patent changes the parameter domain from integer sample positions to fractional sample positions in the timing estimation process. This parameter transformation allows the system to achieve sub-sample accuracy by estimating timing offsets as fractional values rather than discrete integer values, thereby improving measurement precision.
3Measurement precision
If conventional correlation peak detection is used, then the processing speed is high, but the time of arrival estimation accuracy is insufficient
Solution Approach 1:
The patent segments the time of arrival estimation into a fast coarse estimation phase using conventional correlation peak detection and a more accurate fine estimation phase using fractional timing approximation. This segmentation allows the system to quickly eliminate large timing errors in the first phase, then focus computational resources on refining the estimate in the second phase.
Solution Approach 2:
The patent performs preliminary time of arrival estimation using conventional correlation methods to establish a baseline estimate. This preliminary action provides a starting point for the fractional timing approximation, which then refines the estimate by considering fractional sample positions, thereby improving accuracy without completely redoing the estimation process.
Data Source
AI summary
A wireless device includes a receiver to receive a packet via one or more antennas. A frame synchronization detection circuit coupled to the receiver identifies a frame synchronization pattern within a portion of the packet. A correlation circuit coupled to the frame synchronization detection circuit computes one or more values of a correlation peak using a correlation method. A fractional timing approximation circuit coupled to the correlation circuit determines a pulse shape using the one or more values of the correlation peak; and determines a fractional timing approximation for the packet using the pulse shape.