Phase Gain Mismatch Estimation Using Frequency Anomaly Weighting

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Solution Overview

Problem

Existing methods for estimating phase and gain mismatch in OFDM/COFDM signals are biased due to co-channel signals, leading to incorrect signal correction in harsh and mobile environments.

Innovation Solution

A method that detects and weights frequency anomalies in the signal spectrum to provide unbiased estimation of phase and gain mismatch, using segmentation into subbands and computation of weight coefficients to correct the base band digital signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional phase and gain mismatch estimation is used, then the estimation process is simple, but the estimation accuracy deteriorates under co-channel conditions

Engineering Contradiction:

Improvephase and gain mismatch estimation accuracyVSAvoidestimation process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The frequency spectrum is segmented into multiple subbands, and the estimation process is divided into detecting frequency anomalies in each subband and computing weight coefficients. This segmentation allows the system to handle co-channel signals more effectively by treating different frequency regions separately, thereby improving estimation accuracy without requiring a complete redesign of the estimation architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Weight coefficients are introduced as an intermediary element between the raw signal and the final phase/gain mismatch estimation. These coefficients are computed based on detected frequency anomalies and are used to adjust the estimation process, effectively mediating the impact of co-channel signals and improving estimation accuracy under harsh conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If co-channel signals are present, then the signal reception occurs in harsh environments, but the conventional estimation method does not account for frequency anomalies leading to biased results

Engineering Contradiction:

Improvesignal correction reliabilityVSAvoidco-channel signal interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful effect of co-channel signals into useful information by detecting frequency anomalies caused by these signals. The detected anomalies are then used to compute weight coefficients that adjust the estimation process, thereby transforming the previously harmful co-channel interference into a source of corrective information that improves signal reception reliability.

Inventive Principle:

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

Solution Approach 2:

The system implements a feedback mechanism where frequency anomalies are detected, weight coefficients are computed based on these detections, and the phase and gain mismatch estimation is adjusted accordingly. This closed-loop approach continuously adapts to the presence of co-channel signals, improving the reliability of signal correction in harsh environments.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7924955B2Method and article of estimating of phase and gain mismatch and corresponding method and device for receiving a digital base band signal

Publication Date: 2011.04.12 PARROT FAURECIA AUTOMOTIVE SAS

AI summary

The method is for estimating a phase and gain mismatch of a base band digital signal. It comprises:determining (10) weight coefficients depending upon the likelihood of the frequency values of a segment of said base band digital signal; anddetermining (26) the phase and gain mismatch for the segment using the weight coefficients.