US Patent 7171356 Low-power noise characterization over a distributed speech recognition channel

A distributed speech recognition system includes a noise floor estimator to provide a noise floor estimate to a feature extractor which provides a parametric representation of the noise floor estimate. An encoder is included to to generate an encoded parametric representation of the noise floor estimate. A front-end controller is also included to determine when at least one of the noise floor estimator, the feature extractor, and the encoder is to be turned on or off and to determine when the noise floor estimator is to provide the noise floor estimate to the feature extractor. Additionally, a decoder is included to generate a decoded parametric representation of the noise floor estimate. A noise model generator creates a statistical model of noise feature vectors based on the decoded parametric representation of the noise floor estimate.