A new spread spectrum system using spectral correlation technology

2002 ◽  
Author(s):  
Shiping He ◽  
Titus Lo ◽  
J. Litva
Keyword(s):  
Spread Spectrum ◽  
Spectral Correlation

scholarly journals SHAPING OPERATOR TECHNIQUE FOR MODELLING CYCLOSTATIONARY RANDOM PROCESSES

T-Comm ◽  
2021 ◽  
Vol 15 (8) ◽  
pp. 4-12
Author(s):  
Timofey Ya. Shevgunov ◽  
Keyword(s):  
Spread Spectrum ◽  
Linear Time ◽  
Pulse Amplitude ◽  
Delta Function ◽  
Direct Sequence Spread Spectrum ◽  
Analytical Relation ◽  
Operator Technique ◽  
Spectral Correlation ◽  
Dirac Delta ◽  
Linear Time Invariant

The paper proposes the shaping operator technique for modelling cyclostationary random process (CSRP) which belong to the class of second-order processes being described by the parametric pulse train model. Generating CSRP is expressed as the propagation result of the specially chosen elementary CSRP through the linear time-invariant system with a known impulse response. The paper describes the approach to forming the elementary CSRP based on the train made of Dirac delta-function uniformly following in time domain with constant step and defining the desired structural periodicity of the process being modelled. The analytical expressions for the main characteristics used for describing cyclostationary properties of the elementary process, including two-dimensional, cyclic and spectral correlation functions, were obtained. In addition to the case of the elementary CSRP with correlated weighting coefficients of delta-functions, the case of statistically independent coefficients was considered. It was shown that utilization of the spectral correlation function (SCF) for describing the cyclic property reveals the explicit analytical relation between characteristics of the elementary and modelled CSRPs provided the filter frequency response is known. The paper presents the comparative example which describes the modelling of two CSRPs: one of them was chosen as the train of rectangle pulses which is pulse amplitude modulated by stationary random time series, while the other is considered as a signal formed by the method of direct sequence spread spectrum. The chosen short-length Barker sequence as the code allowed performing visual comparison between absolute value of SCF components taken at the cyclic frequencies multiple of the chip frequency and cyclic frequencies multiple of the symbol frequency. The future development of the methods proposed in the paper opens the road to improving the performance of modern radar and telecommunication systems by means of utilizing cyclic frequencies which are non-random parameters describing the structural properties of signals under processing.

Research on Detection Method of Direct Sequence Spread Spectrum Signals

2012 ◽  
Vol 546-547 ◽  
pp. 741-745
Author(s):  
Yun Hang Zhu ◽  
Ming Yuan Deng ◽  
Wei Bing Zhang
Keyword(s):  
Mobile Communications ◽  
Spread Spectrum ◽  
Detection Method ◽  
Satellite Communications ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Spectral Correlation ◽  
Military Tactics ◽  
Communication Ability ◽  
Multi Access

Direct Sequence Spread Spectrum (DSSS) Communication has been widely applied in Personal communications network, WLAN, the third-generation mobile communications, satellite communications systems, military tactics communications and etc, thanks to the DSSS signals’ strong anti-interference ability, low probability of being intercepted and outstanding multi-access communication ability. At the same time, the Problem of estimating Signals has been of great research interest with the development of wind-band weak signals processing and communication antagonism. A new effective detection method of DSSS is proposed, combined the method of wavelet transformation with cycle spectral correlation approach, from the perspective of jamming in non-cooperation condition, and a simulation result of signals--BPSK is given.

Analisis Karakterisasi Teknologi Direct Sequence Spread Spectrum Dan Frequency Hopping Spread Spectrum

2019 ◽  
Vol 2 (2) ◽  
pp. 129-138
Author(s):  
Fawzan Galib Abdul Karim Bawahab ◽  
Elvan Yuniarti ◽  
Edi Kurniawan
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Access ◽  
Frequency Hopping ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Frequency Hopping Spread Spectrum ◽  
Two Systems ◽  
The Difference

Abstrak. Pada penelitian ini, telah dilakukan analisa karakterisasi pada teknologi Direct Sequence Spread Spectrum dan Frequency Hopping Spread Spectrum, sebagai salah satu teknik multiple-access pada sistem komunikasi. Karakterisasi dilakukan untuk mencari bagaimana cara meningkatkan keoptimalan kedua sistem tersebut, dalam mengatasi masalah interferensi dengan sistem dan channel yang sama. Dan juga untuk menentukan veriabel apa yang mempengaruhi keoptimalan kedua sistem tersebut. Karakterisasi dilakukan dengan menentukan variabel-variabel yang mempengaruhi keoptimalan keduanya. Hasil dari karakterisasi, diketahui variabel-variabel yang mempengaruhi kemampuan sistem DSSS yaitu nilai frekuensi spreading (). Sedangkan untuk sistem FHSS yaitu nilai frekuensi spreading ( dan ) dan selisih antara frekuensi hopping data dengan frekuensi hopping interferensi . Kata Kunci: BER, DSSS, FHSS, Interference, Spread spectrum. Abstract. In this study, characterization of Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum technologies have been done, as one of the multiple-access techniques in communication systems. Characterization is done to find out how to improve the ability of the two systems, in solving interference problems with the same system and channel. And also to determine what veriabel affects the ability of the two systems. Characterization is done by determining the variables that affect the ability of both. The results of the characterization, known variables that affect the ability of the DSSS system are the spreading frequency value (). As for the FHSS system, the spreading frequency value ( and ) and the difference between frequency hopping data with frequency hopping interference .

Pre-Processing of Hyperspectral Images Using Nonlinear Filters

2013 ◽  
Vol 11 (1) ◽  
pp. 8-13
Author(s):  
V. Behar ◽  
V. Bogdanova
Keyword(s):  
Signal To Noise Ratio ◽  
Correlation Coefficients ◽  
Hyperspectral Images ◽  
Spectral Correlation ◽  
Edge Preserving ◽  
Improvement Factor ◽  
Filter Output ◽  
Average Improvement ◽  
Processing Procedure

Abstract In this paper the use of a set of nonlinear edge-preserving filters is proposed as a pre-processing stage with the purpose to improve the quality of hyperspectral images before object detection. The capability of each nonlinear filter to improve images, corrupted by spatially and spectrally correlated Gaussian noise, is evaluated in terms of the average Improvement factor in the Peak Signal to Noise Ratio (IPSNR), estimated at the filter output. The simulation results demonstrate that this pre-processing procedure is efficient only in case the spatial and spectral correlation coefficients of noise do not exceed the value of 0.6

Field tests of a spread spectrum land mobile satellite communicationsystem using ETS-V satellite

1992 ◽  
Author(s):  
TETSUSHI IKEGAMI ◽  
SHINICHI TAIRA ◽  
YOSHIYA ARAKAKI ◽  
RYUTARO SUZUKI
Keyword(s):  
Spread Spectrum ◽  
Field Tests ◽  
Mobile Satellite
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