Blind adaptive channel equalization based on affine projection algorithm

In this Letter, we address a novel constant modulus algorithm (CMA) based on affine projection algorithm (APA) for blind equalization transmission channel of QPSK systems to deal with inter symbol interference (ISI). Our algorithm is more rapidly convergence, tracking properties and slightly improved steady-state equalization performance than the same category algorithms such as LMS-CMA and NLMS-CMA, and computationally more efficient with similar convergence compared with least squares algorithm (LS-CMA). Simulation results are presented to compare our APA-CMA algorithm with the blind NLMS-CMA and LS-CMA schemes.