Sensor Role Switching for Noise Reduction in Mobile Devices
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Solution Overview
Problem
Conventional noise reduction systems in mobile communication devices often suffer from signal distortion due to the close proximity of primary and secondary microphones, and incorporating noise reduction functionality increases complexity and cost.
Innovation Solution
The system employs sensors to switch between primary and secondary modes of operation, allowing a first sensor to detect speech and a second sensor to detect noise, or vice versa, and utilizes a processor to compare and subtract signals to provide a noise-reduced output, while also enabling directional sensing to enhance noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary microphone and a secondary microphone are placed close together in a handset, then noise reduction functionality is achieved, but signal distortion occurs due to the close proximity
Solution Approach 1:
The patent combines the functions of primary and secondary microphones by allowing any microphone in the handset to serve as either primary or secondary depending on which one detects less speech. This merging of roles eliminates the need for fixed positional assignments and reduces signal distortion while maintaining noise reduction effectiveness.
Solution Approach 2:
The system dynamically switches the roles of microphones based on real-time detection of speech and noise levels. The processor identifies which microphone detects less speech and assigns it as the secondary microphone, creating a dynamic adaptation that prevents signal distortion while maintaining effective noise reduction.
2Reliability
If noise reduction functionality is incorporated into a headset, then speech quality in noisy environments is improved, but complexity and cost of the headset increases
Solution Approach 1:
The patent makes existing microphones in the handset multi-functional by enabling them to serve as either primary or secondary microphones depending on operating conditions. This universality allows noise reduction functionality to be achieved without adding dedicated secondary microphones, thereby reducing headset complexity and cost while maintaining speech quality in noisy environments.
Solution Approach 2:
The system uses the existing microphones already present in the handset for noise reduction purposes by dynamically assigning roles based on their detection characteristics. This self-service approach eliminates the need for additional dedicated noise reference microphones, reducing device complexity while maintaining effective noise reduction.
3Ease of operation
If traditional handsets disable microphones when headsets are used, then headset functionality is preserved, but noise reduction capability is lost
Solution Approach 1:
The patent merges the noise reduction capability with headset operation by using the handset's existing microphones as noise reference sources when the headset is connected. This merging allows the system to maintain both headset functionality and noise reduction capability simultaneously, overcoming the traditional limitation where microphones are disabled during headset use.
Solution Approach 2:
The system dynamically adapts its microphone configuration based on whether a headset is connected. When a headset is detected, the processor continues to use the handset's microphones for noise reference, dynamically adjusting the noise reduction algorithm to account for the headset's presence while maintaining noise reduction capability that would otherwise be lost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces distortion and improves voice activity detection accuracy in noisy environments by effectively utilizing all sensors for noise reduction, reducing background noise and increasing the accuracy of speech signals.
Implementation Method 1
A processor of the mobile communication device is configured to compare a portion of a representation of the first audio signal that corresponds to the designated time period and a portion of a representation of the second audio signal that corresponds to the designated time period to determine a noise-reduced signal
Data Source
AI summary
Techniques are described herein that use sensors (e.g., microphones) for noise reduction in a mobile communication device. For example, one technique enables a first sensor that is initially configured to be a speech sensor to be used as a noise reference sensor. This technique also enables a second sensor that is initially configured to be a noise reference sensor to be used as a speech sensor. Another technique enables a primary sensor and/or a secondary sensor in a handset of a mobile communication device to be used as a speech sensor while a sensor in a headset of the mobile communication device is used as a noise reference sensor, or vice versa. In yet another technique, a secondary sensor in a mobile communication device is configured to be a directional sensor.