Lower and higher critical band enhancement to attain intelligibility improvement in noisy environment

In mobile communication systems, deterioration in intelligibility of the voiced content of the signal is a commonly observed phenomenon. In order to counter the undesirable effect of background noises on the speech signal, a methodology must be developed such that there is no loss in intelligibility of the speech signal. This work focuses on developing an approach to attain enhancement of speech critical band-wise, when the near-end noise dominates. Two different approaches are employed for speech enhancement. First approach involves enhancing the lower critical bands while the second approach includes higher critical band enhancement. The intelligibility is measured in terms of Speech Intelligibility Index (SII). The SII values infer an improvement in speech intelligibility for higher critical band enhancement.