Improved CMA blind equalization algorithm based on MAP estimation
Lingwei Wang · Jisuanji gongcheng yu sheji · 2010
To solve the problem that constant modulus algorithm(CMA) doesn’t perform well for high-order quadrature amplitude modulation(QAM) signals,an improved blind equalization algorithm is presented,in which CMA is combined with maximum a posteriori(MAP) estimation algorithm.CMA is used to achieve an original convergence,and MAP estimation algorithm is then used to reduce the residual error.Simulation results indicate that improved algorithm has a very fast convergence speed,as well as a very small residual error for high-order QAM signals,and constellation recovery plan is very tight.Meanwhile,the calculation of improved algorithm is less than MAP estimation algorithm,because it needs not to decide which area the signal belongs to.