SHAPING OPERATOR TECHNIQUE FOR MODELLING CYCLOSTATIONARY RANDOM PROCESSES

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.

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PERFORMANCE ANALYSIS OF DS-CDMA SYSTEM FOR UNDERWATER ACOUSTIC COMMUNICATIONS

International Journal of Engineering Applied Sciences and Technology ◽

10.33564/ijeast.2021.v05i09.007 ◽

2021 ◽

Vol 5 (9) ◽

Author(s):

Haoxin Kang

Keyword(s):

Spread Spectrum ◽

Channel Model ◽

Linear Time ◽

Signal To Noise Ratio ◽

Rake Receiver ◽

Direct Sequence Spread Spectrum ◽

Error Rates ◽

Underwater Acoustic Communications ◽

Linear Time Invariant ◽

Scatter Plots

We choose direct sequence spread spectrum (DSSS)technologies combined with Rake receiver under the modulation of BPSK to establish the communication modem. The performance of the modem is extensively investigated by MATLAB based simulation. We analysis the bit error rates (BER) against signal to noise ratio (SNR) corresponding to different parameter settings, for instance, under different Pseudo noise (PN)codes, the long of PN code period, the modulation schemes. Regarding to the Rake receiver, we also compare the scatter plots to deduce whether rake has better performance than without rake, furthermore we change the taps of the rake and diversity combining schemes to continue comparing the BER performance. The modem is implemented in a linear time invariant (LTI)channel model.

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Research on Detection Method of Direct Sequence Spread Spectrum Signals

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.546-547.741 ◽

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.

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Interference excision in direct sequence spread spectrum communication using linear time varient filtr

2011 3rd International Conference on Electronics Computer Technology ◽

10.1109/icectech.2011.5941787 ◽

2011 ◽

Author(s):

N. Murugendrappa ◽

A. G Ananth

Keyword(s):

Spread Spectrum ◽

Linear Time ◽

Direct Sequence Spread Spectrum ◽

Spread Spectrum Communication ◽

Direct Sequence

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Uncertainty remodeling for robust control of linear time-invariant plants^1

Periodica Polytechnica Electrical Engineering ◽

10.3311/pp.ee.2009-1-2.07 ◽

2009 ◽

Vol 53 (1-2) ◽

pp. 55

Author(s):

Gábor Rödönyi ◽

József Bokor

Keyword(s):

Robust Control ◽

Linear Time ◽

Linear Time Invariant ◽

Time Invariant

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

Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics ◽

10.15408/fiziya.v2i2.9513 ◽

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 .

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