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用后置IFFT幅度随机选择器降低OFDM的PAPR
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作者 杨霖 陶欣 《江苏通信》 2008年第S1期15-19,共5页
OFDM和DMT多载波传输系统固有的高峰均功率比(PAPR)能导致功率传输效率的严重退化,特别是用电池作为电源的终端更为严重。目前文献中最常用的PAPR减少技术是选择性映射(SLM)序列技术,它已经达到能把PAPR减少几dB的程度。尽管SLM技术对减... OFDM和DMT多载波传输系统固有的高峰均功率比(PAPR)能导致功率传输效率的严重退化,特别是用电池作为电源的终端更为严重。目前文献中最常用的PAPR减少技术是选择性映射(SLM)序列技术,它已经达到能把PAPR减少几dB的程度。尽管SLM技术对减少PAPR表现得不错,但是实际上,每个OFDM数据串进行传输的时候,它都需要进行多次的IFFT(快速傅里叶变换)运算,这就增加了的系统的复杂性。因此SLM方法有较长的计算时间和较高的功率消耗。建议了一种低复杂度的前置IFFT的PAPR减少方法,它在PAPR减少方面能比SLM方法做得更好,与此同时它的计算复杂度比SLM有较大的减小。 展开更多
关键词 快速傅里叶变换 正交频分复用 峰均功率比 幅度随机序列 计算复杂度
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Effect of Gaussian Noise Amplitude on Translation Error Estimated Using Double-Wayland Algorithm
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《Journal of Mathematics and System Science》 2012年第8期482-488,共7页
The Wayland algorithm has been improved in order to evaluate the degree of visible determinism for dynamical systems that generate time series. The objective of this study is to show that the Double-Wayland algorithm ... The Wayland algorithm has been improved in order to evaluate the degree of visible determinism for dynamical systems that generate time series. The objective of this study is to show that the Double-Wayland algorithm can distinguish between time series generated by a deterministic process and those generated by a stochastic process. The authors conducted numerical analysis of the van der Pol equation and a stochastic differential equation as a deterministic process and a Ganssian stochastic process, respectively. In case of large S/N ratios, the noise term did not affect the translation error derived from time series data, but affected that from the temporal differences of time series. In case of larger noise amplitudes, the translation error from the differences was calculated to be approximately 1 using the Double-Wayland algorithm, and it did not vary in magnitude. Furthermore, the translation error derived from the differenced sequences was considered stable against noise. This novel algorithm was applied to the detection of anomalous signals in some fields of engineering, such as the analysis of railway systems and bio-signals. 展开更多
关键词 Gaussian white noise Wayland algorithm delay time embedding space degree of visible determinism translation error VPE (van der Pol equation) SDE (stochastic differential equation).
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