Speech Quality Estimation Bandwidth Compensation

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Solution Overview

Problem

Existing speech quality estimation methods produce varying quality levels for the same communication system when tested with different bandwidth reference signals, leading to ambiguities in comparing speech quality characteristics of systems or components.

Innovation Solution

Adapting objective speech quality measurement tools to report quality estimates on a unified Super WideBand (SWB) scale, independent of the reference signal bandwidth, by compensating for time delays and gain variations, transforming signals into the perceptual domain, calculating signal distortions, and mapping them to a common scale using bandwidth-specific mappings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If speech quality estimation is performed using different bandwidth reference signals (NB, WB, SWB), then the measurement can accommodate various communication systems and bandwidths, but the results produce varying quality levels for the same system leading to ambiguities in comparison

Engineering Contradiction:
Improvebandwidth compatibilityVSAvoidquality estimation consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by introducing bandwidth compensation parameters that adjust the quality estimation based on the reference signal bandwidth. The system transforms quality estimates from different bandwidths (NB, WB, SWB) to a common reference bandwidth (SWB) using compensation factors, thereby maintaining measurement consistency while preserving adaptability to various bandwidths

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary bandwidth compensation mechanism that mediates between different bandwidth reference signals and the final quality comparison. This intermediary layer normalizes quality estimates by compensating for bandwidth effects, allowing accurate comparison across different bandwidths without losing the ability to handle diverse communication systems

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If objective quality estimation algorithms map internal objective scales to subjective five-grade scales, then the output becomes compatible with traditional subjective testing standards, but the mapping process introduces additional processing steps and potential loss of information

Engineering Contradiction:
Improvescale compatibilityVSAvoidprocessing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing bandwidth compensation and normalization before the final mapping to subjective scales. This preliminary processing ensures that quality estimates are already aligned to a common reference bandwidth, simplifying the subsequent mapping process and reducing information loss during scale transformation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2572356B1Method and arrangement for processing of speech quality estimate
Publication Date: 2015.01.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2572356B1 patent drawingFigure 1
  • EP2572356B1 patent drawingFigure 2a
  • EP2572356B1 patent drawingFigure 2b

AI summary

Method and arrangement for processing of a speech quality estimate, which involve adaption of a speech quality estimate based on information related to the bandwidth of a reference signal used when determining said speech quality estimate, such that the adapted speech quality estimate is independent of the bandwidth of the reference signal. The method and arrangement enable objective speech quality measurements or assessments to be performed on a unified bandwidth scale, independent of the bandwidth of a reference signal, which allows e.g. a more relevant comparison of communication systems and/or equipment, such as e.g. codecs.