  Proportionate-type normalized suband adaptive filter (PNSAF-type) algorithms
are very attractive choices for echo cancellation. To further obtain both fast
convergence rate and low steady-state error, in this paper, a variable step
size (VSS) version of the presented improved PNSAF (IPNSAF) algorithm is
proposed by minimizing the square of the noise-free a posterior subband error
signals. A noniterative shrinkage method is used to recover the noise-free a
priori subband error signals from the noisy subband error signals.
Significantly, the proposed VSS strategy can be applied to any other PNSAF-type
algorithm, since it is independent of the proportionate principles. Simulation
results in the context of acoustic echo cancellation have demonstrated the
effectiveness of the proposed method.
