A modified blind equalization technique based on a constant modulus algorithm

Improved blind equalisation techniques based on a modified constant modulus algorithm (CMA) are proposed. This algorithm can not only accomplish blind equalization and carrier phase recovery simultaneously, but also choose a nonlinear gain with a least-squares algorithm to avoid the gradient noise amplification problem and achieve improved stability and robustness without increasing the computation complexity. It can be switched over to a decision-directed equalization scheme once the error level is reasonably low to obtain higher convergence speed and lower residual intersymbol interference as well. Extensive computer simulation results have verified the analysis and indicated the very attractive behavior of the proposed algorithm.