WOLA noise cancelling performance

The goal of noise cancelling for hearing aids is to remove the noise in the corrupted speech so that the hearing impaired can better understand and participate in a conversation. Most digital hearing aids use a Weighted Overlap-Add (WOLA) structure [1] to implement the noise cancelling algorithm. Often, it is attempted to build a short time Wiener filter with a WOLA either in the FFT or in the Bark domain. Such a filter results in real valued gains to the FFT bins of the input signal and can be easily implemented in the WOLA structure. These real valued gains are also symmetrical with respect to the Nyquist rate, which results in a real valued impulse response from the filter.