IP Telephone Congestion Control by Call-Duration Prioritization

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Solution Overview

Problem

In IP telephone systems, when a line is congested, packets from all calls are uniformly discarded, leading to uniform deterioration of communication quality for all calls, which decreases user satisfaction.

Innovation Solution

A congestion control method that dynamically sets communication parameters based on the number of simultaneous calls and call duration, prioritizing calls with shorter durations to maintain higher quality and allowing calls with longer durations to have lower quality, thereby preventing uniform deterioration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If packets from all calls are uniformly discarded when line is congested, then the line capacity is controlled, but the communication quality of all calls is uniformly deteriorated

Engineering Contradiction:

Improveline capacity controlVSAvoidcommunication quality

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by differentiating packet discard ratios based on individual call characteristics. Instead of uniform discard, each call receives a customized discard ratio determined by its call duration and the current number of simultaneous calls. This ensures that communication quality is maintained differently for each call according to its specific needs, resolving the contradiction between capacity control and quality maintenance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically changes the packet discard ratio parameter based on call duration and congestion level. Calls with shorter durations are assigned lower discard ratios to maintain quality, while calls with longer durations tolerate higher discard ratios. This parameter adjustment resolves the contradiction by adapting quality levels to match call-specific requirements while maintaining overall capacity control.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If calls with longer durations are maintained during congestion, then user communication is secured, but resources are not freed for new calls

Engineering Contradiction:

Improvecall durationVSAvoidcall acceptance rate

Core Design Contradiction:

Duration of action of moving objectVSProductivity

Solution Approach 1:

The patent introduces dynamic quality adjustment based on call duration. During congestion, calls with longer durations are assigned higher packet discard ratios, which dynamically reduces their resource consumption. This allows the system to maintain these calls while freeing sufficient resources for new call admissions, resolving the contradiction between securing ongoing communication and accepting new calls.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the communication quality parameter (packet discard ratio) based on call duration characteristics. By assigning different quality levels to calls of different durations, the system can maintain long-duration calls at reduced quality levels, thereby freeing resources for new calls while still providing communication service to existing users.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If communication quality is maintained high for all calls, then user satisfaction is improved, but line capacity is exceeded during congestion

Engineering Contradiction:

Improvecommunication qualityVSAvoidline capacity

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by assigning different packet discard ratios to different calls based on their duration. Instead of maintaining uniform high quality for all calls, each call receives the quality level appropriate to its characteristics. This resolves the contradiction by maintaining high quality where needed (short-duration calls) while allowing quality degradation where acceptable (long-duration calls), thereby staying within line capacity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the packet discard ratio parameter according to call duration and congestion conditions. By changing this parameter, the system can maintain high communication quality for calls that need it while reducing quality for calls that can tolerate degradation, thus balancing quality maintenance with line capacity constraints during congestion.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12438986B2Congestion control method, congestion control device, and congestion control program

Publication Date: 2025.10.07 NT T INC

AI summary

A congestion control method in an IP telephone system includes processing of acquiring the number of simultaneous calls on one line shared by a plurality of IP telephones, processing of acquiring lengths of call duration of respective calls, and communication parameter setting processing of setting communication parameters that contribute to communication quality of respective calls on the basis of the number of simultaneous calls and the call duration. The call duration of the first call is longer than the call duration of the second call. The communication parameter setting processing includes processing of setting communication parameters such that the communication quality of the first call is worse than the communication quality of the second call in a case where the number of simultaneous calls exceeds a threshold value.