Alphabet Polynomial Fitting criteria for blind equalization

This paper introduces a family of criteria dedicated to blind SISO equalizers. These criteria are based on Alphabet Polynomial Fitting (APF), and remind the well-known Constant Modulus Algorithm (CMA) criterion, and encompass the Constant Power Algorithm (CPA). Two APF-based algorithms have been implemented in block form for QPSK and QAM16 modulated inputs. 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. Finally, APF-QPSK and APF-QAM16 performances are compared with MMSE solutions for various data block lengths.