OFDM Demodulation Timing Offset Correction
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Solution Overview
Problem
The useful information in the cycle prefix of received OFDM signals is typically discarded, leading to suboptimal demodulation performance in OFDM receivers.
Innovation Solution
An OFDM signal demodulation method and device that estimates and adjusts timing offset in real time, allowing for sampling offset correction and maximizing the use of useful information in OFDM frames, thereby improving demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a longer cycle prefix is added to counteract multipath fading with large time delay, then the orthogonality among subcarriers is guaranteed, but power waste increases due to discarding the prefix cycle
Solution Approach 1:
The patent recovers and utilizes the cyclic prefix that was previously discarded. By copying the cyclic prefix to the end of the OFDM symbol and using it for timing offset estimation and correction, the system transforms waste resources into useful information for improving demodulation performance while maintaining subcarrier orthogonality
2Device complexity
If timing offset is not corrected, then device complexity remains low, but demodulation performance deteriorates due to sensitivity to timing offset
Solution Approach 1:
The system uses its own cyclic prefix resources to perform self-correction of timing offset. By estimating timing offset from the received signal's cyclic prefix and applying correction, the system achieves low-complexity timing synchronization without requiring external assistance or complex processing
Solution Approach 2:
The patent dynamically adjusts the FFT window position based on estimated timing offset to optimize the demodulation process. This parameter adjustment allows the system to adapt to timing variations and maintain high demodulation performance while keeping the overall device complexity low
Data Source
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AI summary
The present invention discloses an OFDM signal demodulation method and device thereof. The method comprises: adding a pre-obtained timing offset estimation value of an OFDM signal demodulation device to the initial position of an OFDM symbol of a received signal to obtain a window deviation value of the OFDM symbol; adding a channel time delay extension to the window deviation value to obtain a combined prefix initial position; calculating the combined OFDM signal value starting from the prefix initial position; processing the Fast Fourier Transform (FFT) for the combined OFDM signal value to obtain a frequency domain data subcarrier signal; calculating the frequency domain original channel estimation value processing the channel estimation based on the original channel estimation value phase modification of the OFDM symbol according to the channel estimation compensation indication value; and processing equalization and detection for the frequency domain data subcarrier signal according to the channel estimation result. The present invention uses the cycle prefix of the received signals to promote the demodulation performance of the OFDM signal demodulation device.