Research on Time-Domain Correlation Technique Based on ZC Sequences in OFDM System

2014 ◽  
Vol 519-520 ◽  
pp. 500-503
Author(s):  
Chang Jiang Huang ◽  
Yu Hua ◽  
Yong Hui Hu ◽  
Yu Xiang
Keyword(s):  
Time Domain ◽  
Cross Correlation ◽  
Random Noise ◽  
Correlation Technique ◽  
Ofdm System ◽  
Auto Correlation ◽  
Modulation Signal ◽  
The Time Domain ◽  
Correlation Properties ◽  
Time Domain Correlation

OFDM modulation signal based on different Pseudo-random Noise sequences cant be discriminated in time domain in OFDM system. In order to resolve this problem, the time-domain sliding correlation technique based on ZC sequences is proposed, and the relations between the time-domain correlation properties and the length of the sequence are analyzed. On the basis of the analysis of the technique, the optimum scheme of time-domain sliding correlation is done by the aid of the comparison of the auto-correlation gain on the condition of limited symbol length and band-width. Simulation results in AWGN channel show that OFDM demodulation signal based on ZC sequences designed newly in this work has good auto-correlation and cross-correlation properties in time domain.

Multiple Access Acquisition Technique Based on CAZAC Sequences in OFDM System

2014 ◽  
Vol 513-517 ◽  
pp. 881-884
Author(s):  
Chang Jiang Huang ◽  
Yu Hua ◽  
Yong Hui Hu ◽  
Yu Xiang
Keyword(s):  
Time Domain ◽  
Multiple Access ◽  
Cross Correlation ◽  
Signal Acquisition ◽  
Ofdm System ◽  
Time Domain Signal ◽  
Auto Correlation ◽  
Multiple Frames ◽  
Access Discrimination ◽  
Acquisition Technique

The sliding correlation acquisition technique, which is based on CAZAC sequences in OFDM time-domain multiple access, is proposed and verified. This technique takes advantage of the characteristics of good auto-correlation and cross-correlation characteristics of CAZAC sequences in time domain and achieves the purpose of multiple access discrimination by the different correlation peaks. Whats more, this technique can increase acquisition performance by multiple frames adding up in a receiver according to the receivers demand. The simulation in AWGN channel shows that the technique is feasible and effective in time-domain signal acquisition in OFDM system.

SPMO 8001 Application of time-domain cross-correlation technique to skin blood flow detection

1997 ◽  
Vol 23 ◽  
pp. S145
Author(s):  
F. Gens ◽  
J.P. Remenieras ◽  
S. Diridollou ◽  
Y. Gall ◽  
F. Patat ◽  
...  
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Time Domain ◽  
Cross Correlation ◽  
Correlation Technique ◽  
Flow Detection ◽  
Cross Correlation Technique

scholarly journals A skewed perspective of the Indian rainfall–El Niño–Southern Oscillation (ENSO) relationship

2020 ◽  
Vol 24 (11) ◽  
pp. 5473-5489 ◽  
Author(s):  
Justin Schulte ◽  
Frederick Policielli ◽  
Benjamin Zaitchik
Keyword(s):  
Time Series ◽  
Time Domain ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Wavelet Coherence ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Time Domain ◽  
Time Domain Correlation

Abstract. Wavelet coherence is a method that is commonly used in hydrology to extract scale-dependent, nonstationary relationships between time series. However, we show that the method cannot always determine why the time-domain correlation between two time series changes in time. We show that, even for stationary coherence, the time-domain correlation between two time series weakens if at least one of the time series has changing skewness. To overcome this drawback, a nonlinear coherence method is proposed to quantify the cross-correlation between nonlinear modes embedded in the time series. It is shown that nonlinear coherence and auto-bicoherence spectra can provide additional insight into changing time-domain correlations. The new method is applied to the El Niño–Southern Oscillation (ENSO) and all-India rainfall (AIR), which is intricately linked to hydrological processes across the Indian subcontinent. The nonlinear coherence analysis showed that the skewness of AIR is weakly correlated with that of two ENSO time series after the 1970s, indicating that increases in ENSO skewness after the 1970s at least partially contributed to the weakening ENSO–AIR relationship in recent decades. The implication of this result is that the intensity of skewed El Niño events is likely to overestimate India's drought severity, which was the case in the 1997 monsoon season, a time point when the nonlinear wavelet coherence between AIR and ENSO reached its lowest value in the 1871–2016 period. We determined that the association between the weakening ENSO–AIR relationship and ENSO nonlinearity could reflect the contribution of different nonlinear ENSO modes to ENSO diversity.

Research on the Existence Detection of DSSS Signal Based on Auto-Correlation

2014 ◽  
Vol 513-517 ◽  
pp. 2963-2966 ◽  
Author(s):  
Yan Li Shi ◽  
Chun Mei Du ◽  
Lin Ren ◽  
Hai Xia Yu
Keyword(s):  
Spread Spectrum ◽  
Theoretical Foundation ◽  
Detection Method ◽  
Practical Application ◽  
Application Range ◽  
Practical Applications ◽  
Auto Correlation ◽  
Power Spectral ◽  
The Time Domain ◽  
Time Domain Correlation

In practical applications, the DSSS signal has very low power spectral density, and its application range is very wide, so in the non cooperative communication, if on the premise that the spread spectrum sequence is unaware, how to detect and estimate the existence of DSSS signal is very important, this has very strong application background. This paper introduces the time domain correlation detection method of DSSS signal, through the simulation can validate that this way can detect the existence of signal; it lays the theoretical foundation for practical application.

scholarly journals Cross-Correlation of THz Pulses from the Electron Storage Ring BESSY II

2020 ◽  
Vol 5 (2) ◽  
pp. 24
Author(s):  
Ulrich Schade ◽  
Peter Kuske ◽  
Jongseok Lee ◽  
Barbara Marchetti ◽  
Michele Ortolani
Keyword(s):  
Synchrotron Radiation ◽  
Storage Ring ◽  
Time Domain ◽  
Cross Correlation ◽  
Bunch Length ◽  
Pump Probe ◽  
Electron Storage ◽  
Coherent Synchrotron Radiation ◽  
Longitudinal Length ◽  
The Time Domain

Coherent synchrotron radiation from an electron storage ring is observed in the THz spectral range when the bunch length is shortened down to the sub-mm-range. With increasing stored current, the bunch becomes longitudinally unstable and modulates the THz emission in the time domain. These micro-instabilities are investigated at the electron storage ring BESSY II by means of cross-correlation of the THz fields from successive bunches. The investigations allow deriving the longitudinal length scale of the micro bunch fluctuations and show that it grows faster than the current-dependent bunch length. Our findings will help to set the limits for the possible time resolution for pump-probe experiments achieved with coherent THz synchrotron radiation from a storage ring.

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