基于修正变换域降噪的NC-OFDM信道估计算法  

Channel Estimation Method with Modified Noise Reduction in Transform Domain for NC-OFDM Systems

作　　者：王军[1] 李洪宇[1] 张世昌[1] 李少谦[1] 

机构地区：[1]电子科技大学通信抗干扰技术国家级重点实验室,成都610054

出　　处：《电子科技大学学报》2009年第5期639-643,共5页Journal of University of Electronic Science and Technology of China

基　　金：国家863计划(2007AA10Z209;2009AA012002;2009AA011801);国家基础科研项目(A1420080150);国家973计划(2009CB320405)

摘　　要：针对NC-OFDM系统在某些相干带宽内可能没有足够的导引符号,导致基于频域内插的LS信道估计算法性能较差的问题,提出了一种修正变换域降噪的信道估计算法。该算法利用NC-OFDM系统信道衰落系数的时频域关系,通过IDFT在时域估计信道多径衰落,并进行降噪滤波,然后采用DFT估计频域信道衰落系数,从而避免了频域内插。仿真结果表明,在仿真条件下,该方法比传统基于频域内插的LS信道估计有约4dB的性能增益。In order to enhance channel estimation performance of NC-OFDM systems in the case of lacking enough pilot symbols, a novel channel estimation scheme with modified noise reduction in transform domain is proposed. Channel multipath fading coefficients are estimated by inverse discrete Fourier transform （IDFT） in time domain based on the relationship between time and frequency domain expressions of the channel fading coefficients of NC-OFDM systems. Noise reduction filtering is performed in time domain. Finaly, the channel fading coefficients are obtained in frequency domain by discrete Fourier transform （DFT） without interpolation. Simulation results show the proposed channel estimation scheme outperforms the conventional LS estimation with a gain of about 4dB.

关 键 词：信道估计 认知无线电 NC—OFDM 变换域降噪 

分 类 号：TN92[电子电信—通信与信息系统]