There's plenty of room at the bottom: Incremental combinations of sign-error LMS filters

The introduction of data reuse in the incremental topology made it possible for combinations of LMS filters to outperform algorithms such as the Affine Projection Algorithm (APA) with lower complexity. This work poses and extends the concept of combinations as a complexity reduction technique by proposing an incremental combination of sign-error LMS filters that matches and even outperforms stand-alone LMS filters with reduced complexity. This combination is then analyzed and used as a building block in a larger combination that is able to match the APA at a reduced computational cost. Numerical simulations illustrate the performance of this novel combination in different scenarios.