Voice Quality Estimation Using Burst Loss Sequence Mapping

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Solution Overview

Problem

Conventional voice quality estimation methods, such as the E-model, fail to accurately capture sudden quality degradation caused by burst-like packet losses, and do not effectively quantify the influence of packet losses that occur in a specific range, leading to inaccurate voice quality assessment.

Innovation Solution

A voice quality estimation apparatus that creates sequences reflecting characteristics of immediate quality degradation perception, degradation likelihood, and packet loss concealment, and calculates degradation amounts per unit time using a mapping function to estimate user-experienced voice quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the E-model uses average burst loss length (BurstR) for voice quality estimation, then the calculation is simplified and can be performed with basic network parameters, but it cannot accurately capture sudden quality degradation caused by different burst loss distributions

Engineering Contradiction:
Improvecalculation simplicityVSAvoidvoice quality estimation accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent segments the packet loss sequence into individual loss events with specific temporal positions and intervals. Instead of using a single average BurstR value, the method divides the loss pattern into discrete elements (loss positions, inter-loss intervals) that can be individually analyzed and weighted according to their impact on perceived quality, thereby capturing distribution characteristics while maintaining computational feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the traditional single-parameter BurstR approach into a multi-parameter model that includes loss position, inter-loss interval, and weighted degradation amounts. By changing from an average-based parameter to a set of distributed parameters with different weights, the system can accurately represent different burst loss distributions and their impact on voice quality perception.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the evaluation criterion monotonically increases degradation amount with continuous packet loss period, then the calculation method is straightforward, but it cannot accurately grasp the influence of packet losses that suddenly occur all at once in a certain range

Engineering Contradiction:
Improveevaluation calculation simplicityVSAvoidburst loss impact measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies local quality by assigning different weights to different positions and intervals within the packet loss sequence. Instead of uniform treatment of all losses, the method gives higher weights to losses that occur in positions perceived as more impactful by users (e.g., silent periods, transition regions) and uses different weighting for inter-loss intervals, thereby accurately capturing the localized impact of burst losses while maintaining a systematic evaluation framework.

Inventive Principle:
Principle #3Local quality

3Device complexity

If conventional voice quality estimation methods are used, then the implementation is simple and relies on basic network indicators, but sudden quality degradation caused by burst-like packet losses cannot be accurately captured

Engineering Contradiction:
Improveestimation system complexityVSAvoidquality degradation detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces dynamics by making the degradation amount variable based on loss position and inter-loss interval characteristics. The weighting factors are not static but adapt according to the specific pattern of packet losses, allowing the system to dynamically respond to different burst loss scenarios. This dynamic approach improves detection reliability for sudden quality degradation while keeping the underlying calculation framework relatively simple.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11749297B2Audio quality estimation apparatus, audio quality estimation method and program
Publication Date: 2023.09.05 NIPPON TELEGRAPH & TELEPHONE CORP
  • US11749297B2 patent drawing
  • US11749297B2 patent drawing
  • US11749297B2 patent drawing

AI summary

A voice quality estimation apparatus includes: a packet sequence creation unit configured to create a first sequence by applying a first characteristic indicating that quality degradation caused by packet loss is perceived by a user all at once, to a sequence consisting of elements each indicating whether or not a packet of a voice call has been lost; a smoothing unit configured to create a second sequence from the first sequence; a degradation amount emphasis unit configured to create a third sequence from the second sequence; a packet loss tolerance characteristics reflection unit configured to create a fourth sequence from the third sequence; a degradation amount calculation unit configured to calculate a degradation amount from the fourth sequence; and a listening quality estimation unit configured to estimate voice quality that is to be experienced by the user, from the degradation amount.