双选择性衰落信道下的改进型频域判决反馈均衡  

A Modified Frequency-Domain Decision-Feedback Equalization for Doubly-Selective Fading Channels

作　　者：冯昂[1] 张莹[1] 邓科[1] 

机构地区：[1]西安交通大学智能网络与网络安全教育部重点实验室,西安710049

出　　处：《西安交通大学学报》2010年第10期67-71,共5页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基(60772095;60971113);教育部高等学校博士学科点专项科研基金资助项目(200806980020)

摘　　要：针对双选择性衰落信道下传统频域判决反馈均衡(FD-DFE)会遭受严重性能损失的问题,提出一种新的重叠保留频域判决反馈均衡(OLS-FD-DFE)算法.首先,在设计前馈滤波器时,通过对其取值范围做出约束,使得有效抽头只在指定区间内存在非0值.然后,利用重叠保留法,将数据块分割为多个子块再进行频域均衡,如果子块长度小于信道相干时宽,只要在均衡每个子块时依据信道响应更新滤波器系数,就可以明显提高对信道时变的容忍度.仿真结果表明,当移动速度为100km/h时,OLS-FD-DFE算法在信噪比20dB处的误码率可以达到2×10-5,而相同情况下FD-DFE算法的误码率只能达到8×10-4.A novel overlap-save frequency-domain decision-feedback equalizer（OLS-FD-DFE）is proposed to improve the problem that the conventional frequency-domain decision-feedback equalizer（FD-DFE）suffers from severe performance detriment in doubly-selective fading channels.The feedforward filter is designed with constraint on its time-domain values such that the effective taps have non-zero values only in a predefined range.Then,the overlap-save method is applied to divide the original block-wise convolution into several subblock-wise convolutions.When the length of subblock is less than the coherence time of the channel,the tolerance to the channel time-variation can be significantly improved,as long as the filter coefficients are updated according to the channel response.Simulation results show that if the mobile moves at the speed of 100 km/h,OLS-FD-DFE achieves 2×10-5 bit error rate when the signal-to-noise ratio is 20dB,while FD-DFE achieves only 8×10-4 bit error rate in the same scenario.

关 键 词：单载波调制 频域均衡 重叠保留 判决反馈均衡 

分 类 号：TN911.7[电子电信—通信与信息系统]