MIMO Reception Apparatus Relative Delay Correction
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Solution Overview
Problem
In MIMO communication systems, especially for mobile terminals, precise synchronization and delay correction are challenging due to hardware constraints and environmental factors, leading to signal attenuation and unreliable demodulation, particularly when relative delays occur between transmission paths.
Innovation Solution
A reception apparatus and method that detect and correct relative delays within one IFFT chip by using specific frequency components for synchronization acquisition and phase correction, ensuring accurate synchronization and channel estimation, even in the presence of multipath delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO transmission is performed by a mobile terminal, then communication speed is improved, but synchronization precision deteriorates due to hardware constraints and environmental factors
Solution Approach 1:
The patent applies preliminary action by performing delay detection and correction before main signal processing. The reception apparatus detects relative delays between MIMO transmission paths using correlation detection on received signals, then corrects these delays by adjusting the timing of signals from different antennas. This preliminary correction ensures that subsequent signal processing operates on synchronized inputs, resolving the synchronization precision issue while maintaining MIMO's high-speed communication capability
Solution Approach 2:
The patent implements feedback by using correlation detection to continuously monitor and detect relative delays between transmission paths. The system calculates correlation values between signals from different antennas, identifies timing offsets based on peak correlation positions, and feeds this delay information back to the timing adjustment mechanism. This closed-loop feedback ensures continuous synchronization correction, maintaining precision despite hardware constraints and environmental variations
2Measurement precision
If FFT frame detection is performed, then signal synchronization is improved, but orthogonality of subcarriers deteriorates when timing is misaligned
Solution Approach 1:
The patent applies preliminary action by performing correlation-based delay detection before FFT frame detection and processing. The system detects the relative timing offsets between MIMO transmission paths using correlation detection on the received signals, then corrects these delays by adjusting signal timing. This preliminary synchronization correction ensures that subsequent FFT operations are performed on properly aligned signals, preventing intersymbol interference and maintaining subcarrier orthogonality
Solution Approach 2:
The patent segments the signal processing into distinct stages: first performing correlation detection to identify delay characteristics, then applying timing correction based on detected delays, and finally performing FFT processing. This segmentation allows the system to address synchronization issues separately before main signal processing, ensuring that orthogonality is preserved during the critical FFT operation while still achieving accurate frame detection
3Adaptability or versatility
If relative delays between transmission paths occur, then MIMO transmission flexibility is improved, but signal demodulation reliability deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring relative delays between MIMO transmission paths using correlation detection. The system calculates correlation values between signals from different antennas, identifies timing offsets based on peak positions, and feeds this delay information back to the timing adjustment mechanism. This closed-loop feedback ensures that demodulation reliability is maintained despite the presence of relative delays, allowing the system to operate flexibly with mobile terminals while preserving signal integrity
Solution Approach 2:
The patent replaces the need for high-precision hardware synchronization (mechanical system) with signal processing-based delay detection and correction. Instead of relying on perfectly synchronized hardware clocks in mobile terminals, the system uses correlation detection to measure actual delays and applies software-based timing adjustments. This substitution allows MIMO transmission flexibility with mobile terminals while maintaining demodulation reliability through intelligent signal processing
Data Source
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AI summary
An electronic device that digitizes a baseband signal obtained from a received high-frequency signal; specifies a position of a preamble included in the digitalized signal; calculates a square of the preamble; specifies a peak from a value obtained by the square of the preamble; perfonns a fast Fourier transform (FFT) on the baseband signal using a position of the peak as a start of an FFT window; extracts phases of a plurality of frequency components for phase measurement from the baseband signal which has been subjected to the FFT; obtains a phase difference of the plurality of phases; and obtains a phase correction value of a reception signal using the phase difference and a phase reference.