Speech enhancement using a remote wireless microphone

Noise reduction is an important problem in hands-free speech capture. This paper discusses the use of a remote wireless microphone to aid the reduction of practical non-stationary noise signals. Such a microphone can be placed close to a noise source to provide a reliable estimate of the undesired signal, which can be used by a noise reduction algorithm. The signal from the remote microphone, however, needs to be wirelessly transmitted to the primary device where the noise reduction is performed. As the remote and primary microphones are located on separate devices, their signals need not be synchronously sampled. Moreover, wireless transmission of data is power-intensive, requiring techniques to reduce the transmission bit-rate. This paper discusses transmission of the time domain signal and frequency domain parameters, analyzes their respective trade-offs between performance and robustness to synchronization errors, and presents methods to reduce the transmission bit-rate.