卫星通信中改进型变步长LMS预失真算法  

An Improved Variable Step-Size LMS Algorithm for Predistortion in Satellite Communication

作　　者：李良山[1] 杨育红[1] 王兰[1] 

机构地区：[1]解放军信息工程大学,河南郑州450002

出　　处：《雷达科学与技术》2016年第2期140-145,共6页Radar Science and Technology

基　　金：国家自然科学基金(No.61379006;61171108)

摘　　要：针对传统多项式预失真算法解决高功率放大器非线性失真时存在收敛速度慢和稳态均方误差大的缺点,将多项式预失真应用于卫星通信系统中,提出了一种改进型变步长LMS(Improved Variable Step-Size Least Mean Square,IP-VSSLMS)算法。该算法通过利用误差信号及误差信号与输入信号的平均能量,获得了一种新的变步长因子,有效地增强了步长因子的动态调整能力,提高了收敛速度和降低了均方误差。仿真结果表明,IP-VSSLMS算法能够有效地抑制信号的星座扭曲和频谱再生,解决了高功率放大器非线性失真的问题,相比传统算法,能够获得更快的收敛速度和较小的稳态均方误差。When traditional polynomial predistortion algorithm is used to compensate nonlinear distortion of high power amplifier,there occur the defects of the slow convergence speed and big steady state mean square error.To counteract these disadvantages,polynomial predistortion is applied in satellite communication system and an improved variable step-size least mean square algorithm is proposed.Furthermore,a new variable step-size factor is obtained by using the error signal and the average energy of error signal and input signal.The algorithm can effectively enhance the ability of dynamic adjustment for step-size factor.Therefore,the algorithm improves the convergence speed and reduces steady state mean square error.Simulation results show the IP-VSSLMS algorithm can effectively suppress the constellation wrapping and spectrum regrowth,and solve the nonlinear distortion of high power amplifier.Moreover,the algorithm can achieve faster convergence speed and smaller steady state mean square error when compared with the traditional algorithms.

关 键 词：卫星通信 非线性 预失真 LMS算法 

分 类 号：TN927[电子电信—通信与信息系统]