Adaptive blind equalizers with whitening filters

Owing to the multimodality of the constant modulus (CM) cost surfaces, poor initializations of the adaptive blind equalizer (BE) employing the constant modulus algorithm (CMA) may converge to undesired local minima, thus preventing the adaptive BE from opening eye. This paper conducts theoretical analyses via the CM cost surfaces and demonstrates that the use of the BE in tandem with a whitening filter (WF) may still open eye even if the BE based on the CM criterion converges to an undesired local minimum, whereas in the same situation the use of the BE alone may not achieve eye opening. Computer simulations were also conducted to verify our results.