Adaptive Channel Equalization via Dynamic Window Filtering

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Solution Overview

Problem

Existing channel equalization methods in OFDM systems face inaccuracies due to noise-induced jitter in channel transfer matrices, particularly when using fixed sliding window lengths for noise filtering, which can lead to suboptimal compensation of intersymbol interference in wideband communications.

Innovation Solution

The method involves acquiring a channel transfer matrix based on a training sequence, deriving an amplitude response matrix to dynamically determine the optimal window length for noise filtering, and performing adaptive noise filtering to obtain an optimal channel equalization, thereby reducing intersymbol interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mean noise filtering processing is performed using a fixed preset window length of sliding window, then noise filtering is implemented, but channel equalization accuracy deteriorates due to inability to adapt to different channel conditions

Engineering Contradiction:
Improvechannel equalization accuracyVSAvoidadaptability to different channel conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by transforming the fixed preset window length into a dynamic variable that adapts to different channel conditions. The window length is determined based on the amplitude response matrix characteristics, allowing the filtering process to automatically adjust its parameters according to the actual channel state, thereby resolving the contradiction between maintaining fixed simplicity and achieving adaptive accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of window length from a fixed preset value to a variable determined by channel characteristics. By calculating the amplitude response matrix and using its properties to set the window length, the system dynamically adjusts the filtering parameters to match the channel conditions, improving equalization accuracy without requiring manual intervention.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If channel transfer matrix is obtained based on training sequence, then channel estimation is performed, but jitter occurs due to noise impact

Engineering Contradiction:
Improvechannel transfer matrix accuracyVSAvoidnoise-induced jitter
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an amplitude response matrix as an intermediary between the noisy channel transfer matrix and the final equalization process. This intermediary structure allows the system to extract stable characteristics from the noisy data by analyzing amplitude responses, thereby reducing the impact of noise-induced jitter while preserving essential channel information.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of noise into a beneficial filtering mechanism. By using the amplitude response matrix to determine the optimal window length for sliding window filtering, the system transforms noise contamination into an opportunity to apply adaptive noise reduction, where the noise characteristics themselves inform the filtering parameters that will subsequently reduce their impact.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP2991298B1Channel equalization method and device, and receiver
Publication Date: 2018.01.31 HUAWEI TECH CO LTD
  • EP2991298B1 patent drawingFigure 1
  • EP2991298B1 patent drawingFigure 2
  • EP2991298B1 patent drawingFigure 3

AI summary

Embodiments of the present invention provide a channel equalization method and apparatus, and a receiver. The method includes: acquiring a channel transfer matrix according to a training sequence sent by a transmit end; acquiring an amplitude response matrix of the channel transfer matrix, and acquiring, according to the amplitude response matrix, a window length of a sliding window that is required for performing noise filtering on the channel transfer matrix; and performing noise filtering on the channel transfer matrix according to the window length of the sliding window, and performing, according to a channel transfer matrix that is obtained by means of noise filtering, channel equalization on a data payload sent by the transmit end. The channel equalization method and apparatus, and a receiver provided in the embodiments of the present invention may implement adaptive channel equalization.