Blind equalizers based on polynomial criteria

We describe a family of criteria dedicated to blind SISO equalizers. These criteria are based on alphabet polynomial fitting (APF), and remind us of the well-known constant modulus algorithm (CMA) criterion, and encompass the constant power algorithm (CPA) criterion. Algorithms based on several polynomial criteria have been implemented in block form (including CPA and APF), as well as the CMA and the kurtosis maximization (KMA). Block implementations are indeed more efficient for short data records, and allow the direct computation of the optimal step size in a gradient descent, as shown in the paper. Computational complexities of APF, KMA and CMA are eventually compared, as well as their performance for various digitally modulated inputs.