A combination of two adaptive algorithms SMI and CMA

Constant Modulus Algorithm (CMA) is a method that has been widely known as blind adaptive beamforming because it requires no knowledge about the signa l except that the transmitted signal waveform has a constant envelope. Alth ough CMA has the merit of this blind operation, it possesses problems in it s convergence property. In this paper, problems that are inherent to this, algorithm is resolved using a combination of CMA and another major adaptive algorithm SR II (Sample Matrix Inversion). The idea is to use SR II to det ermine the initial weights for CMA operation. Although the benefit of CMA b eing a blind algorithm is not fully taken advantage of, good aspects of bot h SMI and CMA carl be introduced. By using this approach, two major problem s in convergence properties of CMA can be solved. One of these problems is the reliability and this relates to the convergence performance ill certain cases. When the interfering signal is stronger than the desired signal, th e algorithm tends to come up with the wrong solution by capturing the inter fering signal which has the stronger power. Also, the convergence time? of this algorithm is slow, limiting its application in dynamic environment, al though the slow convergence time of CMA has been studied previously and sev eral methods hale been proposed to overcome this defect. Using the proposed method. the deterioration due to both of these problems can be mitigated. Simulation results are shown to confirm the theory. Furthermore, evaluation s are done concerning the fading characteristics. It is also confirmed from tile simulation that the tracking performance of this method can be regard ed as sufficient in personal mobile communication.