一种基于分数阶傅里叶变换的OFDM系统及其均衡算法  

The OFDM System and Equalization Algorithm Based on the Fractional Fourier Transform

作　　者：陈恩庆[1] 陶然[1] 张卫强[2] 孟祥意[1] 

机构地区：[1]北京理工大学电子工程系 [2]清华大学电子工程系,北京100084

出　　处：《电子学报》2007年第3期409-414,共6页Acta Electronica Sinica

基　　金：国家自然科学基金项目(No.60572094);国家部委基金项目(No.6140445)

摘　　要：在快速时变信道环境下,由于子载波间干扰(ICI)的影响,传统OFDM系统性能有较大下降.本文提出了一种基于分数阶傅里叶变换的OFDM系统,它用分数阶傅里叶变换代替傅里叶变换进行子载波调制与解调;同时,文中给出了最优分数阶傅里叶变换阶次的选取方法,并根据最小均方误差(MMSE)准则设计了分数阶傅里叶域乘性滤波器在接收端进行均衡.分析和数值仿真结果表明,最优分数阶傅里叶域的乘性滤波算法较频域方法有更好的均衡效果.The performance of traditional OFDM system is greatly degraded in time-varying fading channel due to the intercarrier interference （ICI）. This paper proposes an OFDM system based on the fractional Fourier transform in which traditional Fourier transform is replaced by fractional Fourier transform to modulate and demodulate the symbols. The algorithm for selecting the optimal order of fractional Fourier transform is derived. Moreover, the multiplication fdter in fractional Fourier domain is designed according to the minimum mean square error （MMSE） criterion to equalize the received signal. Theoretical analysis and numerical simulation results show that the proposed equalizer in optimal fractional Fourier domain can significantly improve the performance of OFDM compared with Fourier domain equalizer.

关 键 词：分数阶傅里叶变换 OFDM 时变信道 信道均衡 

分 类 号：TN911.5[电子电信—通信与信息系统]