MIMO系统中的非常数模半盲均衡方案

A Semi-blind Equalization Scheme of Non-constant Modulus in a MIMO System

在多输入多输出(Multiple-Input Multiple-Output,MIMO)无线通信中,信道衰落、随机噪声、空间多径效应和共信道干扰等因素会产生符号间干扰,造成接收端信号严重失真。为提高MIMO系统传输性能,有效减少信道中相位失真,提出了一种改进的非常数模半盲均衡方案(Non-constant Modulus Algorithm,NCMA)。该方案结合了MIMO信道先验知识对半盲均衡器的初始值进行预设,采用变步长迭代更新均衡器权系数,寻找到最小目标函数值。仿真结果表明,改进后的算法能通过控制变步长减小剩余稳态误差,加快收敛速度,改善信道均衡效果。

In multiple-input multiple-output(MIMO)wireless communication,factors such as channel fading,random noise,spatial multipath effect,and co-channel interference can produce inter-symbol interference(ISI),which causes serious signal distortion in the receiving terminal.In order to improve the transmission performance in a MIMO system,effectively reduce the phase distortion in the channel,an improved semi-blind equalization scheme of Non-constant Modulus Algorithm(NCMA)is proposed.This scheme combines the prior knowledge of the MIMO channel,presets the initial value of the semi-blind equalizer,uses variable step-size to iterate and update the weight coefficients of the equalizer,and finds the minimum objective function value.The simulation results show that the improved algorithm can reduce the residual steady-state error,accelerate the convergence speed,and improve the channel equalization effect by controlling the variable step-size.