Blind equalisation technique based on an improved constant modulus adaptive algorithm

A blind equalisation technique based on an improved constant modulus adaptive (CMA) algorithm is proposed. This technique can accomplish blind equalisation and carrier phase recovery simultaneously as well as easily switch between blind and decision-directed modes. It also takes advantage of the principle of minimum disturbance to avoid the gradient noise amplification problem and achieve improved stability and robustness with low computational complexity. It can be easily switched over to a decision-directed equalisation scheme whenever the error level is reasonably low to obtain higher convergence speed and lower residual intersymbol interference as well. Computer simulation results have indicated very attractive behaviour of the proposed technique, especially with respect to various noise characteristics and time-varying channels.