OFDM系统在时变信道下的迭代干扰抵消算法  

Iterative interference cancellation for OFDM systems in time-varying channels

作　　者：李司坤[1] 王宗欣[1] 

机构地区：[1]复旦大学通信科学与工程系,上海200433

出　　处：《高技术通讯》2009年第4期372-376,共5页Chinese High Technology Letters

基　　金：国家自然科学基金(60572124)资助项目

摘　　要：为克服正交频分复用(OFDM)系统中因时变多径衰落信道破坏子载波的正交性引起载波间干扰(ICI),从而导致系统性能下降的问题,提出了一种基于最小均方误差(MMSE)估计和迭代算法相结合的迭代干扰抵消算法。为了消除一般MMSE均衡方法将载波间干扰当作加性高斯白噪声(AWGN)所带来的误差,该算法先使用MMSE方法对传输信号进行初值估计,再通过迭代干扰抵消和MMSE均衡相结合,来消除由时变信道所带来的载波间干扰。多次仿真表明,在时变多径衰落信道中使用本算法能够有效地消除载波间干扰,使系统性能得到很好的改善。To overcome the problem that the time-varying multipath fading channel in an orthogonal frequency division multiplexing （OFDM） system leads to the loss of subcarrier orthogonality which in turn causes the inter-cartier interference （ICI） and increases the system＇s inaccuracy in signal detection, this paper proposes an iterative ICI cancellation algorithm based on the combination of the minimum mean square error （MMSE） estimation with the iterative algorithm. To avoid the inaccurate assumption in conventional one-tap ICI cancellation that ICI is modeled as the additive white Gaussian noise （AWGN）, the algorithm uses the MMSE principle to estimate the initial value of the transmitted signal, and then eliminates the ICI caused by the time-varying muhipath fading channel by the iterative ICI cancellation and MMSE equalization. The extensive simulations show that through a small number of iterations the ICI can be cancelled effective- ly, and the system performance can be improved.

关 键 词：正交频分复用(OFDM) 载波间干扰(ICI) 最小均方误差(MMSE) 干扰抵消 迭代检测 

分 类 号：TN919.3[电子电信—通信与信息系统]