Communication Device Noise Reduction via Dynamic Codebook Selection

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Solution Overview

Problem

Cellular communication devices face challenges in noisy environments where background noise is encoded along with voice signals, affecting the device's performance and intelligibility.

Innovation Solution

A communication device with a processing module that selects codebooks based on signal-to-noise ratio to generate coded signals with reduced noise, using high resolution codebooks for low noise and lower resolution codebooks for high noise conditions, effectively attenuating unwanted noise components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If speech coding is performed in noisy environments, then communication can be maintained, but noise is encoded along with voice signals reducing intelligibility

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidspeech intelligibility
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent extracts and removes the noise component from the digital speech signal before encoding. The noise removal module separates the noise from the voice signal, allowing only the cleaned speech to be encoded, thereby preventing noise from being transmitted while maintaining communication reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies noise removal as a preliminary action before speech coding. By removing noise from the digital speech signal prior to encoding, the system ensures that only clean speech information is transmitted, preventing noise from degrading speech intelligibility in the encoded signal

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If high resolution codebooks are used for speech coding, then speech quality is improved, but device complexity increases

Engineering Contradiction:
Improvespeech coding precisionVSAvoidcodebook complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic codebook selection where the resolution of codebooks varies based on the noise level in the environment. In low-noise conditions, high-resolution codebooks are used for better speech quality, while in high-noise conditions, the system switches to alternative strategies. This dynamic adaptation optimizes speech coding precision while managing device complexity by not always using the highest resolution codebooks

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2309498B1A communication device with reduced noise speech coding
Publication Date: 2016.11.09 BROADCOM INC
  • EP2309498B1 patent drawingFigure 1
  • EP2309498B1 patent drawingFigure 2
  • EP2309498B1 patent drawingFigure 3~4

AI summary

A communication device includes memory, an input interface, a processing module, and a transmitter. The processing module receives a digital signal from the input interface, wherein the digital signal includes a desired digital signal component and an undesired digital signal component. The processing module identifies one of a plurality of codebooks based on the undesired digital signal component. The processing module then identifies a codebook entry from the one of the plurality of codebooks based on the desired digital signal component to produce a selected codebook entry. The processing module then generates a coded signal based on the selected codebook entry, wherein the coded signal includes a substantially unattenuated representation of the desired digital signal component and an attenuated representation of the undesired digital signal component. The transmitter converts the coded signal into an outbound signal in accordance with a signaling protocol and transmits it.