Study of the Fast Semi-Blind Equalization Algorithm for the QAM Communication System
Xue Haiwe · Electronic Science and Technology · 2015
Due to the inter-symbol interference( ISI) and co-channel interference( CCI) of the MIMO convolutional communication system driven by QAM signals,a combined semi-blind equalization algorithm( CSBEA) is proposed by utilizing the selectivity of the soft decision directed( SDD) algorithm and the geometric properties of constellation of QAM signals. This algorithm overcomes the maladjustment in the steady state of constant modulus algorithm and multimodulus algorithm and avoids the problems of a rapidly increased computational load of SDD algorithm of high order QAM systems. Furthermore,the gradient Newton method is adopted to optimize the cost function of the proposed CSBEA,which brings about a faster convergence speed and a better steady state performance than that of gradient-type algorithms. Finally,several experiments are provided to illustrate the effectiveness of the proposed method.