Carrier Frequency Offset Estimation Using Multi-Delay Correlation
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Solution Overview
Problem
Existing carrier frequency offset estimation methods in 802.11b wireless LANs face challenges in achieving high accuracy and a wide acquisition range simultaneously due to phase ambiguity issues.
Innovation Solution
The method involves using at least two frequency offset estimation apparatuses with different delay parameters to correlate a preamble sequence with a Barker code, extracting peak values, and combining the results to calculate a final carrier frequency offset estimate, ensuring both high accuracy and a suitable acquisition range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single delay parameter is used in carrier frequency offset estimation, then the estimation process is simple, but either estimation accuracy or acquisition range cannot be simultaneously optimized
Solution Approach 1:
The patent divides the frequency offset estimation into multiple segments by using multiple frequency offset estimation apparatuses with different delay parameters. Each apparatus handles a specific portion of the estimation task, allowing the system to achieve both high accuracy and wide acquisition range without requiring a single overly complex apparatus.
Solution Approach 2:
The patent merges the outputs of multiple frequency offset estimation apparatuses with different delay parameters into a final carrier frequency offset estimate. This combining approach allows the system to leverage the strengths of each individual apparatus while achieving overall superior performance in both accuracy and acquisition range.
2Adaptability or versatility
If a small delay is used in the delayed correlation method, then the estimation range is wide, but the estimation accuracy deteriorates
Solution Approach 1:
The patent applies local quality by assigning different delay parameters to different frequency offset estimation apparatuses based on their specific functional requirements. Some apparatuses use smaller delays for wider estimation range, while others use larger delays for higher accuracy, allowing each local component to optimize for its specific purpose.
3Measurement precision
If a greater delay is used in the delayed correlation method, then the estimation accuracy is higher, but the estimation range becomes narrower due to phase ambiguity
Solution Approach 1:
The patent introduces another dimension by using multiple delay parameters simultaneously rather than relying on a single delay value. This multi-dimensional approach allows the system to overcome the trade-off between accuracy and range by examining the estimation results from multiple different delay perspectives and synthesizing a final accurate estimate.
Data Source
AI summary
Methods, system and apparatuses for carrier frequency offset estimation are disclosed. The method includes: receiving a preamble sequence rn with a correlator and correlating the preamble sequence with a locally stored Barker code bn to obtain a correlation result cn; extracting peak values from every L points in cn to form a peak value sequence xn, L being a length of a Barker code that corresponds to the sampling rate; performing frequency offset estimation to xn by using at least two frequency offset estimation apparatuses, the at least two frequency offset estimation apparatuses adopting different delay parameters D; and inputting the results output from the at least two frequency offset estimation apparatuses into a frequency offset combination module to calculate a final carrier frequency offset estimate, whereby accurate frequency estimation can be achieved and an appropriate acquisition range of frequency offset can be ensured.