Wireless Device Key Change Noise Reduction

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Solution Overview

Problem

Existing wireless communication systems for cordless telephones face challenges in maintaining secure and reliable encryption key changes during calls, leading to potential noise and audio interruptions due to sequence errors and reception errors.

Innovation Solution

The system implements a method for dynamic encryption key changes by using a timer to initiate key changes and employs audio reduction mechanisms to manage errors, ensuring seamless transitions between encrypted and unencrypted states, thereby reducing noise and improving call quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption key changes are performed dynamically during calls, then security performance is improved, but sequence errors and reception errors occur leading to noise and audio interruptions

Engineering Contradiction:
Improvesecurity performanceVSAvoidnoise and audio interruptions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary error detection by checking sequence numbers of received frames before completing the encryption key change. When a sequence error is detected, the key change process is aborted and the original key is maintained, preventing noise and audio interruptions caused by using incorrect encryption keys.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms by continuously monitoring reception errors and sequence numbers during encryption key changes. Based on the feedback from error detection, the system dynamically adjusts the key change process - either completing it successfully or aborting it to maintain audio quality.

Inventive Principle:
Principle #23Feedback

2Reliability

If encryption is activated immediately after wireless link establishment, then security is improved, but complexity of key management increases

Engineering Contradiction:
ImprovesecurityVSAvoidkey management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements self-service key management where the same key is used for both encryption and identification purposes. This eliminates the need for separate key management mechanisms, reducing complexity while maintaining security during the initial phase of communication.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If audio reduction is performed when sequence errors occur, then audio quality is maintained, but call continuity may be affected

Engineering Contradiction:
Improveaudio qualityVSAvoidcall continuity
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The system performs preliminary detection of sequence errors before they can cause audio degradation. By detecting sequence number mismatches early in the key change process, the system can abort the key change and maintain the original encryption key, preventing audio quality degradation while maintaining call continuity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system prepares for potential sequence errors by having the original encryption key ready as a backup. When a sequence error is detected, the system seamlessly switches back to the original key without interrupting the call, cushioning against potential audio quality issues.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3128695B1Wireless communications device and control method for wireless communications device
Publication Date: 2021.02.24 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3128695B1 patent drawingFigure 1~2
  • EP3128695B1 patent drawingFigure 3~5
  • EP3128695B1 patent drawingFigure 6

AI summary

A wireless communications device is constituted from a control station and a slave station that perform encryption communication using an encryption key and changes the encryption key in a predetermined procedure, during a call, and the device includes a controller that operates in such a manner that audio is reduced, if the procedure in which the encryption key is changed is not correctly executed, in a case where a change of the encryption key is made.