Improved LMS estimation via structural detection

In various adaptive estimation applications, the unknown channel is characterized by an impulse response which consists of extended regions of negligible response or `inactivity´. We consider the LMS estimation of a channel that may be well approximated by an FIR (filter) model with only a few nonzero tap coefficients within a given delay horizon or tap length n. When the number of nonzero tap coefficients m is small compared to the delay horizon n, the performance of the LMS estimator is greatly enhanced when this specific structure is exploited. We propose a consistent algorithm that performs identification of nonzero taps only