Blind Frequency Domain Equalization Using Ryy Estimation
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Solution Overview
Problem
Current frequency domain equalization methods in receivers, such as HSDPA/WCDMA, require significant resources for monitoring interfering cells and noise estimation, and introduce errors due to matrix approximation, leading to computational complexity and resource intensity.
Innovation Solution
Direct estimation of the Ryy term in the frequency domain using element-wise multiplication of the received signal and its conjugate, exploiting the relationship between circular correlation and convolution, reduces resource requirements and minimizes errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If frequency domain equalization is implemented using traditional methods with matrix approximation, then equalization can be performed in the frequency domain, but computational complexity and resource intensity increase significantly
Solution Approach 1:
The patent extracts and estimates only the essential Ryy term in the frequency domain using element-wise multiplication of received signal and its conjugate, rather than performing full matrix approximation. This selective extraction reduces computational complexity while maintaining the core equalization functionality.
Solution Approach 2:
The patent uses element-wise multiplication of the received signal with its conjugate to create a frequency domain representation that copies the essential correlation information of Ryy. This copying approach avoids the need for complex full matrix operations while preserving the necessary equalization data.
2Reliability
If traditional frequency domain equalization methods are used requiring monitoring of interfering cells and noise estimation, then comprehensive interference mitigation can be achieved, but resource requirements increase
Solution Approach 1:
The patent enables the system to estimate the Ryy term directly from the received signal itself through element-wise multiplication with its conjugate. This self-service approach eliminates the need for separate resource-intensive monitoring of interfering cells and noise estimation, as the received signal contains the necessary information for estimation.
3Ease of manufacture
If matrix approximation is used in frequency domain equalization, then the equalization process can be simplified, but estimation errors are introduced
Solution Approach 1:
The patent creates a frequency domain copy of the Ryy term through element-wise multiplication of the received signal and its conjugate. This copying method preserves the exact correlation information without the approximation errors inherent in traditional matrix approximation methods, thereby maintaining high estimation accuracy.
Data Source
AI summary
A frequency domain chip-level equalizer is disclosed. The equalizer includes an estimation module configured to generate a frequency domain estimate of an auto-correlation function of a received signal; and an equalization module configured to apply frequency domain equalization to the received signal using the frequency domain estimate of the auto-correlation function to generate frequency domain equalized samples of the received signal. The equalizer further includes an Inverse Fast Fourier Transform (IFFT) module configured to generate time domain equalized samples of the received signal from the frequency domain equalized samples.