OFDM Receiver SNR-Based Weighting for Inter-Carrier Interference
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Solution Overview
Problem
Existing OFDM receivers face challenges in effectively suppressing inter-carrier interference and noise signals, particularly in environments with large channel changes, where simple summation of sample data from symbol interference-free and effective symbol intervals fails to achieve significant signal-to-noise ratio gain.
Innovation Solution
The method involves performing a weighting operation on the sample data from the symbol interference-free and effective symbol intervals based on measured signal-to-noise ratios (SNRs), using a maximum ratio combining approach to generate FFT input data, which reduces noise and improves SNR by adaptively combining data from both intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple summation of sample data from symbol interference-free and effective symbol intervals is performed, then device complexity is reduced, but signal-to-noise ratio gain is insufficient in environments with large channel changes
Solution Approach 1:
The patent changes the parameter of combining weights from equal weights to SNR-based weights. By measuring the SNR of each interval and using these measurements to determine weighting factors, the system adapts to channel conditions dynamically, resolving the contradiction between simple operation and reliable performance
Solution Approach 2:
The system uses its own measured SNR values to automatically determine the optimal combining weights without requiring external control or complex algorithms. The measured SNR directly serves as the basis for weight calculation, enabling the system to self-optimize based on current channel conditions
2Ease of operation
If equal weight values (0.5) are assigned to both intervals, then ease of operation is improved, but the SNR gain from larger interval is not achieved
Solution Approach 1:
The patent transitions from static equal weighting to dynamic SNR-based weighting. The weights are no longer fixed at 0.5 but vary dynamically based on the measured SNR conditions of each interval, allowing the system to adapt to changing channel characteristics while maintaining operational simplicity through automated measurement and calculation
3Reliability
If maximum ratio combining with SNR-based weighting is performed, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the measured SNR of each interval is fed back into the weighting calculation. This closed-loop approach allows the system to automatically adjust weights based on actual performance, achieving optimal SNR gain while keeping the complexity manageable through a direct and efficient feedback path
Data Source
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AI summary
Disclosed is a method for suppressing an inter-carrier interference and noise signal, and an orthogonal frequency division multiplexing receiver for performing the same. Here, a method for an orthogonal frequency division multiplex (OFDM) receiver to suppress an inter-carrier interference and noise signal by using a symbol interference free interval without inter-symbol interference (ISI) in a guard interval (GI) includes: performing a weighting operation between sample data of the symbol interference free interval and sample data of the effective symbol interval by using a signal-to-noise ratio (SNR) of the symbol interference free interval and an SNR of an effective symbol interval corresponding to the symbol interference free interval; and performing a fast Fourier transform (FFT) on FFT input data configured by including the weighting-operated sample data into the effective symbol interval.