Fig. 1. Block diagram for an adaptive echo cancellation configuration.[4], we define the degree of sparsity of a chanlle] as a qualitative measure ranging from strongly dispersive (when most of the coefficients of W o (n) are active) to strongly sparse.It is a well-known fact that adaptive schemes which distribute the adaptation energy equally among all filter coefficients~such as least-mean-square (LMS) and normalized LMS (NLI\1S), exhibit a very slow convergence for filters with many taps [5, 6], making the application of such schemes unpractical for the cancellation of sparse echo channels. To alleviate this problem, the proportionate NLMS algorithm (PNLMS)[7] makes the adaptation step for each tap proportional to the current absolute value of the estimated weight, i.e, s(n) + eo(n) d(n)