On a Variable-step Constant-modulus Blind Equalization Algorithm Modified by Memory Gradient Method
Dong Yu-hua · Dalian Minzu Xueyuan xuebao · 2010
The traditional constant modulus blind equalization algrithm has defects including a slow convergence rate and,under a fixed step,conflicts between convergence rate and precision.Against those defects,this paper proposes a variable-step,constant-modulus,blind equalization algorithm modified by a memory gradient method.The equalizer weights are adjusted by the memory gradient method instead of the steepest descent algorithm.The new algorithm makes full use of gradient information on current and previous iteration points,while using gradient information changing rate as the learning step adjustment factor.It increases the convergence rate and,compared with other modified algorithms such as conjugate gradient and quasi-Newton methods,has lower computational complexity and better equalization performance.Computer emulation proved the effectiveness of this algorithm.