A new variable step-size algorithm on acoustic feedback suppression for digital hearing aids

Acoustic feedback suppression is a key task of digital hearing aid which commonly uses least mean square (LMS) or normalized LMS(NLMS) adaptive algorithm to cancel acoustic feedback signal, however the characteristic of acoustic feedback signal is not considered in these algorithms. In order to improve the listening recognition of hearing-impaired patients, this paper proposes a new variable step-size improved proportionate NLMS(IPNLMS) algorithm which bases on the sparseness of echo impulse. According to the nonlinear relationship between step size and error signal, this paper proposes a variable step-size IPNLMS adaptive algorithm which adds a step smooth process. The simulation results show that the proposed algorithm has more excellent performance for noise-canceling acoustic feedback of digital hearing aids, comparing with others variable step-size IPNLMS adaptive algorithms.