OFDM Phase Error Correction via Selective Signal Extraction

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Solution Overview

Problem

Existing methods for correcting phase errors in demodulation signals, such as those used in mobile communication terminals, are inefficient and inaccurate due to poor acquisition of frequency-to-phase characteristics, leading to unsynchronized phase correction.

Innovation Solution

A receiving device and method that includes a reception unit, demodulation unit, ideal constellation signal generation, data extraction, phase error calculation, phase error characteristic estimation, and phase error correction units to accurately and efficiently correct phase errors in OFDM demodulation signals by selecting reliable signal data for estimation and correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phase error correction is performed using all signal data in the frequency section, then the correction comprehensively covers the entire signal, but the accuracy of frequency-to-phase characteristic acquisition deteriorates due to inclusion of unreliable signal data

Engineering Contradiction:

Improvephase error correction accuracyVSAvoidsignal data reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The frequency section is divided into multiple sub-frequency sections, and signal data is selectively extracted from specific sub-frequency sections where the signal quality is reliable. This segmentation allows the system to avoid using unreliable signal data while maintaining comprehensive phase error correction across the entire frequency spectrum.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the frequency spectrum are treated differently based on signal quality. The system identifies and selects signal data from frequency regions with reliable characteristics, applying phase error correction using only these high-quality local segments rather than uniformly processing all frequency data.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If phase error correction uses only a part of signal data, then the accuracy of frequency-to-phase characteristic acquisition improves, but the comprehensiveness of phase error correction deteriorates

Engineering Contradiction:

Improvefrequency-to-phase characteristic acquisition accuracyVSAvoidphase error correction comprehensiveness

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system uses an intermediary approach by selecting representative signal data from specific frequency sections as mediators to estimate the overall phase error characteristics. These selected signal segments serve as proxies that capture the essential phase error behavior without requiring processing of all signal data, thus maintaining both accuracy and comprehensiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The phase error characteristic estimation derived from selected signal data is applied universally to correct phase errors across the entire frequency spectrum. The correction parameters obtained from reliable signal segments are generalized to compensate for phase errors in all frequency regions, achieving comprehensive correction through localized measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional phase synchronization methods are used, then the process is simple, but the phase error correction accuracy deteriorates due to inadequate frequency-to-phase characteristic acquisition

Engineering Contradiction:

Improvephase synchronization process simplicityVSAvoidphase error correction accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary selection and extraction of reliable signal data before conducting phase error calculation and characteristic estimation. This preliminary action ensures that only high-quality signal data is used in the subsequent phase synchronization process, improving accuracy without significantly complicating the overall workflow.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the conventional mechanical approach of uniformly processing all signal data with a selective extraction mechanism that identifies and uses only reliable signal segments. This substitution introduces intelligent data selection based on signal quality metrics, improving phase error correction accuracy while maintaining operational simplicity through automated quality assessment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11528121B2Receiving device and receiving method, and mobile terminal test apparatus provided with receiving device

Publication Date: 2022.12.13 ANRITSU CORP

AI summary

Included are a demodulation unit that demodulates a received OFDM modulation signal to acquire a demodulated constellation signal, an ideal constellation signal generation unit that generates an ideal constellation signal from the demodulated constellation signal, a data extraction unit that extracts signal data corresponding to subcarriers included in a part of an intermediate frequency section among all frequency sections, from the demodulated constellation signal and the ideal constellation signal, a phase error calculation unit that calculates the phase error of the demodulated constellation signal for the ideal constellation signal, with respect to the extracted signal data, a phase error characteristic estimation unit that estimates the frequency characteristic of the phase error, and a phase error correction unit that corrects the phase error of the demodulated constellation signal, based on the frequency characteristic of the phase error.