Frequency Offset Pre-Compensation Using Historical Decoding States
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Solution Overview
Problem
Current methods for eliminating frequency offset in wireless communication systems, particularly in high-speed scenarios like high-speed railways, face inaccuracies due to errors in coarse frequency offset estimation, leading to incorrect demodulation and decoding.
Innovation Solution
A method that compares the current frequency offset state with historical effective states for accurate pre-compensation, using amplitude limiting and frequency domain continuation strategies based on signal/noise ratios and frame number differences to improve fine frequency offset estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic prefix is used for coarse frequency offset estimation and pre-compensation, then the frequency offset can be estimated and compensated, but the estimation error is huge or even invalid due to low signal/noise ratio in actual environment
Solution Approach 1:
The patent performs coarse frequency offset estimation using cyclic prefix before fine frequency offset estimation. By doing the coarse estimation first and then refining it with pilot signals, the system prepares the signal in advance for more accurate fine estimation, improving overall frequency offset compensation accuracy in low signal/noise ratio environments
Solution Approach 2:
The patent uses feedback from the coarse frequency offset estimation result to guide the fine frequency offset estimation process. The coarse estimation result is used as a reference to adjust and refine the fine estimation, creating a feedback loop that improves measurement precision while maintaining reliability
2Reliability
If Doppler shift compensation is performed to eliminate the influence of Doppler shift, then the frequency offset can be reduced, but the complexity of the system increases due to multiple compensation steps required
Solution Approach 1:
The patent divides frequency offset compensation into two distinct segments: coarse frequency offset compensation using cyclic prefix, and fine frequency offset compensation using pilot signals. This segmentation allows each stage to focus on specific aspects of compensation, reducing overall system complexity while maintaining high accuracy
Solution Approach 2:
The patent performs preliminary coarse frequency offset compensation using cyclic prefix before the main fine compensation stage. This preliminary action removes the bulk of the frequency offset early in the process, simplifying subsequent fine compensation operations and reducing the complexity of the overall system
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and stability of frequency offset estimation, reduces computational complexity, and improves upstream throughput in high-speed communication environments by leveraging historical correct decoding states for pre-compensation.
Implementation Method 1
Due to the frequency offset between the transmitting device and the receiving device, and the Doppler shift caused by the movement of the transmitting device in the wireless communication system
Data Source
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AI summary
The present invention discloses a method and system for processing frequency offset, the method includes: obtaining a current frequency offset state; determining whether the current frequency offset state is consistent with a historical effective frequency offset state; wherein the historical effective frequency offset state is a frequency offset state corresponding to a correct decoding result; if it is determined yes, performing a pre-compensation to a fine frequency offset estimation according to the historical effective frequency offset state. The present application solves the problem that inaccurate frequency offset estimation makes it unable to perform frequency offset compensate.