共查询到16条相似文献,搜索用时 78 毫秒
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一种用于OFDM符号定时跟踪的盲估计算法 总被引:1,自引:0,他引:1
利用具有循环前缀和循环后缀的OFDM帧结构,该文提出了一种新的符号定时跟踪盲估计算法。理论分析及仿真表明,无论在AWGN还是多径衰落信道条件下,该定时算法估计的均方差都小于ML算法。 相似文献
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本文提出了一种新的适合于OFDM系统的符号定时估计算法。该算法利用经过特殊处理的前后两段信息序列的内在相关性进行准确的符号定时估计。理论分析和仿真表明,该算法能在大频偏低信噪比的条件下完成定时捕获的任务,并且无需专门的训练符号,从而大大提高了系统传输的效率。 相似文献
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基于循环谱包络的扩谱直序信号的码片时宽、载频、幅度估计 总被引:40,自引:3,他引:40
扩谱直序信号是二阶循环平稳信号,其循环谱幅度包了信号的码片的时宽、载频、幅度等信息,通过分析,文中提出利用非零循环频率处谱峰的位置与大小估计这三个参数的算法,算法不需要伪随机码序列和信号参数等先验信息,可实现对信号参数的盲估计;对参数的估计是非零循环频率上进行两个一维搜索,很大程度避免或减小了平稳噪声和干扰的影响,适用于低信噪比情况,且避免了多维搜索;文中还分析了算法的实现条件,并通过仿真实验对估计算法性能进行评估。 相似文献
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基于循环前缀的OFDM系统定时同步估计算法 总被引:1,自引:1,他引:0
正交频分复用(OFDM)是一种多载波高效调制技术,由于能够有效地对抗无线环境中多径信道引起的码间干扰(ISI),近些年来受到越来越广泛的关注.同步是一切数字通信系统能够有效工作的基础.由于OFDM相对于单载波通信系统对同步误差更加敏感,因此同步技术更是OFDM系统中最关键技术之一.文中定量分析了符号定时同步误差对系统性能的影响,并详细给出了基于循环前缀的符号定时同步估计算法及其性能分析.通过仿真对各基于循环前缀同步估计算法进行了比较,给出了算法的应用场三合. 相似文献
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针对OFDM(正交频分复用)符号粗同步定时点会随路径能量变动的缺点,利用信道估计得出的信道脉冲响应,提出一种基于能量收集的精同步算法,不需设定判决门限,得到的最终定时点能有效避免ISI(符号间干扰)和ICI(信道间干扰)的引入.多径信道中的仿真验证了该算法的良好性能. 相似文献
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在OFDM系统中用导频符号进行信道估计的新方法 总被引:15,自引:10,他引:5
对信道的准确估计是提高相干解调的正交频分复用(OFDM)系统性能的关键,利用在OFDM系统中信道的频域响应是过采样的特性,提出了在频域内用均匀梳状分布的导频符号和导频符号数相同点的傅里叶变换相结合扒道估计方法,在16QAM OFDM系统中将其与带低通滤波器的Isi(sin(x)/x) 插值法,cubic插值法和Winner插值法进行了信道估计的均方误差和无编码的误比特率捻 真结果进行了比较,其结果表明本方法的估计性能优于si和cubic插值法,并接近优化的Win-ner插值法但其计算复杂度与Winner插值法相比却大大降低。 相似文献
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In this paper the problem of data-aided symbol timing and frequency offset estimation in OFDM systems is considered. A synchronization
scheme based on a pilot symbol containing two identical parts obtained by transmitting BPSK data symbols on the even subcarriers
and setting zero on the remaining subcarriers is proposed. In this case, if the number of subcarriers is sufficiently large,
the pilot symbol can be modeled as a noncircular (NC) complex Gaussian random vector (CGRV). By exploiting the joint probability
density function of NC-CGRVs, the joint maximum likelihood estimator for the parameters of interest is derived. Since its
implementation complexity is high, a simpler synchronization scheme is obtained. Moreover, refined symbol timing and frequency
offset estimators, that assure relevant performance in multipath channels, are proposed.
T. Fusco was born in Naples, Italy, on March 22, 1977. She received the Dr. Eng. degree (summa cum laude) in electronic engineering
from the Second University of Napoli in 2002. Since November 2002 she has been a Ph.D. student at the Department of Electronic
and Telecommunication Engineering of the University of Napoli Federico II. Her current research and study interests lie in
the area of statistical signal processing, with emphasis on parameter estimation problems in the context of OFDM communications.
M. Tanda was born in Aversa, Italy, on July 15, 1963. He received the Dr. Eng. degree (summa cum laude) in electronic engineering
in 1987 and the Ph.D. degree in electronic and computer engineering in 1992, both from the University of Napoli Federico II.
Since 1995, he has been an Appointed Professor of Signal Theory an the University of Napoli Fe-de-ri-co II. Moreover, he has
been an Appointed Professor of Electrical Communications (from 1996 until 1997) and Telecommunication Systems (from 1997)
at the Second University of Napoli. He is currently Associate Professor of Signal Theory at the University of Napoli Federico
II. His research activity is in the area of signal detection and estimation, multicarrier, and multiple access communication
systems. 相似文献
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大频偏低信噪比条件下OFDM系统中的符号定时估计 总被引:1,自引:1,他引:0
符号定时估计是OFDM系统中的关键问题之一,该文就此问题提出了一种新的基于训练符号的定时估计算法。研究表明,新算法的性能基本不受载波频偏的影响,且具有很强的抗噪特性。通过采用这种算法可将定时误差缩小到只有抽样时间间隔的一半。并且,还可利用这个频域训练符号来进行载波频偏的估计,从而只需一个训练符号就能完成符号定时和载波频偏的联合捕获。 相似文献