| 基于多项式模型的OFDM信道盲估计 |
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| 引用本文： | 方承志,都思丹,薛卫.基于多项式模型的OFDM信道盲估计[J].东南大学学报,2007,23(2):162-167. |
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| 作者姓名： | 方承志 都思丹 薛卫 |
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| 作者单位： | 南京大学电子科学与工程系 南京210093 |
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| 摘 要： | 采用二元多项式模型对时变OFDM系统的时频响应进行建模.在多项式模型的基础上,结合期望最大化(EM)方法的思想,提出了一种利用时频面上的二维数据来获取模型参数的最大似然(ML)估计值的算法(PEMTO).为了降低计算复杂度,避免由于矩阵求逆而带来的风险,给出了PEMTO的一种迭代计算方法(RPEMTO)PEMTO算法在数学上进行简化后,可以用来进行一维序贯信道估计.仿真结果显示,所提出算法的误码率低于其他类型的盲估计算法.
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| 关 键 词： | 正交频分复用 期望最大化(EM) 多项式模型 迭代 |
| 修稿时间： | 2007-01-08 |
OFDM blind channel estimation based on polynomial models |
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| Fang Chengzhi,Du Sidan,Xue Wei.OFDM blind channel estimation based on polynomial models[J].Journal of Southeast University(English Edition),2007,23(2):162-167. |
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| Authors: | Fang Chengzhi Du Sidan Xue Wei |
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| Institution: | Department of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China |
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| Abstract: | A two-dimensional (2-D) polynomial regression model is set up to approximate the time-frequency response of slowly time-varying orthogonal frequency-division multiplexing (OFDM) systems.With this model the estimation of the OFDM time-frequency response is turned into the optimization of some time-invariant model parameters.A new algorithm based on the expectation-maximization (EM) method is proposed to obtain the maximum-likelihood (ML) estimation of the polynomial model parameters over the 2-D observed data.At the same time,in order to reduce the complexity and avoid the computation instability, a novel recursive approach (RPEMTO) is given to calculate the values of the parameters.It is further shown that this 2-D polynomial EM-based algorithm for time-varying OFDM (PEMTO) can be simplified mathematically to handle the one-dimensional sequential estimation.Simulations illustrate that the proposed algorithms achieve a lower bit error rate (BER) than other blind algorithms. |
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| Keywords: | orthogonal frequency-division multiplexing expectation-maximization polynomial model recursive |
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