Apparatus and method for voice activity detection in a communication system
First Claim
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1. A method for voice activity detection (VAD) within a communication system, the method comprising the steps of:
- estimating a signal characteristic of an input signal;
estimating a noise characteristic of the input signal;
estimating a signal-to-noise ratio (SNR) of the input signal based on the estimated signal and noise characteristics;
estimating the variability of the noise characteristic;
deriving a VAD threshold based on the estimated SNR; and
biasing the VAD threshold based on the variability of the noise characteristic.
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Abstract
In order for the Voice Activity Detector (VAD) decision to overcome the problem of being over-sensitive to fluctuating, non-stationary background noise conditions, a bias factor is used to increase the threshold on which the VAD decision is based. This bias factor is derived from an estimate of the variability of the background noise estimate. The variability estimate is further based on negative values of the instantaneous SNR.
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17 Claims
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1. A method for voice activity detection (VAD) within a communication system, the method comprising the steps of:
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estimating a signal characteristic of an input signal;
estimating a noise characteristic of the input signal;
estimating a signal-to-noise ratio (SNR) of the input signal based on the estimated signal and noise characteristics;
estimating the variability of the noise characteristic;
deriving a VAD threshold based on the estimated SNR; and
biasing the VAD threshold based on the variability of the noise characteristic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus comprising a Voice Activity Detection (VAD) system for detecting voice in a signal wherein the VAD system detects voice by estimating a signal-to-noise ratio (SNR) of an input signal, estimating a variation (μ
- ) in the estimated SNR, deriving a VAD threshold based on the estimated SNR, and biasing the VAD threshold based on a variation of the estimated SNR.
- View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for estimating the variability of the background noise within a communication system, the method comprising the steps of:
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estimating a signal characteristic of an input signal;
estimating a noise characteristic of the input signal;
estimating a signal-to-noise ratio (SNR) of the input signal based on the estimated signal and noise characteristics; and
updating the estimate of the variability of the background noise when the current estimate of the SNR is less than a threshold. - View Dependent Claims (17)
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Specification