| 摘要: |
| 为提高目前无线通信系统中正交频分复用（Orthogonal Frequency Division Multiplexing，OFDM）技术下的信道估计性能，分析了基于离散傅里叶变换(Discrete Fourier Transform，DFT)的信道估计算法存在的缺陷。针对传统DFT信道估计算法没有考虑循环前缀内噪声的影响和非整数倍时延信道下存在能量泄露的问题，提出了一种基于信噪比（SignaltoNoise Ratio，SNR）估计的改进DFT信道估计算法。在最小二乘（Least Square，LS）算法的基础上，经过频域加窗处理后利用导频序列估计系统信噪比，将其转化为循环前缀内的降噪阈值门限，并进行两次降噪操作。仿真结果表明，改进后的算法不但可以有效地消除循环前缀内的噪声，而且在非整数倍时延信道下能够抑制能量泄露的影响，具有比传统DFT信道估计算法更好的性能。 |
| 关键词: 正交频分复用 信道估计 能量泄露 信噪比估计 |
| DOI： |
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| 基金项目:2019年重庆市技术创新与应用发展专项重大主题专项(cstc2019jscx zdztzxX0002) |
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| An improved DFT channel estimation algorithm based on SNR estimation in OFDM system |
| ZHOU Weihai,CHENG Fang,DENG Bingguang,WU Ting |
| (School of Communication and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China) |
| Abstract: |
| In order to improve the channel estimation performance under the orthogonal frequency division multiplexing(OFDM) technology in current wireless communication systems,the defects of the channel estimation algorithm based on discrete Fourier transform(DFT) are studied.In view of the problem that the traditional DFT channel estimation algorithm does not consider the influence of noise in the cyclic prefix and there exists energy leakage in non-integer delay channels,an improved DFT channel estimation algorithm based on signal-to-noise ratio(SNR) estimation is proposed.Based on the Least Square(LS) algorithm,the SNR of the system is estimated by the pilot sequence after windowing in the frequency domain,which is transformed into the denoising threshold in the cyclic prefix,and the denoising operation is carried out twice.Simulation results show that the improved algorithm can not only effectively eliminate the noise in the loop prefix,but also suppress the influence of energy leakage in the non-integer multiple delay channels,and has better performance than the traditional DFT channel estimation algorithm. |
| Key words: orthogonal frequency division multiplexing channel estimation energy leakage SNR estimation |
