DC Offset Correction Using Period-Matched Moving Average Filtering
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Solution Overview
Problem
In wireless communication systems, particularly those using OFDM, the injection of a DC component can lead to performance degradation due to uncorrected DC offsets, which result in higher data error rates, especially at higher data rates.
Innovation Solution
A method and system for removing DC offset from a signal involves receiving a radio frequency signal, converting it to a digital signal, correcting for carrier frequency offset, and using a moving average filter and differentiator to remove the DC offset, ensuring the signal is processed without transmitter and receiver DC offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a moving average filter matched to the period is applied to remove the periodic component, then the DC offset removal accuracy is improved, but the processing complexity increases
Solution Approach 1:
The DC offset correction process is segmented into distinct stages: periodic component removal using moving average filter, DC offset estimation from the filtered signal, and final DC offset correction. This segmentation allows each stage to be optimized independently, improving overall accuracy while managing complexity through modular processing
Solution Approach 2:
The periodic component is removed in advance using a moving average filter matched to the signal period before DC offset estimation. This preliminary action isolates the DC offset component, enabling more accurate measurement and correction while simplifying the subsequent processing steps
2Measurement precision
If carrier frequency offset correction is applied before DC offset removal, then the DC offset measurement accuracy is improved, but the overall processing time increases
Solution Approach 1:
Carrier frequency offset correction is performed as a preliminary step before DC offset removal. This ensures that the signal is properly frequency-aligned, which improves the accuracy of subsequent DC offset measurement and removal operations
Solution Approach 2:
The processing pipeline maintains continuous operation by performing carrier frequency offset correction and DC offset removal in sequential stages without interrupting the signal flow. This continuous processing minimizes overall latency while ensuring each correction step is performed with optimal accuracy
Data Source
AI summary
Systems and methods for removing DC offset from a signal are provided. A radio frequency signal is received at a receiver. The radio frequency signal is converted into a digital signal including a periodic component with a period. A carrier frequency offset is removed from the digital signal to generate a frequency-shifted digital signal. The frequency-shifted digital signal is filtered to remove a DC offset in the digital signal. The filtering includes applying a moving average filter matched to the period to remove the periodic component from the frequency-shifted digital signal. The moving average filter generates a set of average values based on the frequency-shifted digital signal. The filtering also includes taking a difference between consecutive values of the set of average values to determine the DC offset, where the DC offset is introduced at the receiver.