Parameter Estimation of the Direct Sequence Spread Spectrum Signal Based on Time-Smoothing Cyclic Periodogram

2012 ◽  
Vol 195-196 ◽  
pp. 181-185
Author(s):  
Peng Zheng ◽  
Feng Liu ◽  
Xin Zhang
Keyword(s):  
Parameter Estimation ◽  
Spread Spectrum ◽  
Code Rate ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Limited Data ◽  
Simulation Results ◽  
Digital Communication System ◽  
Data Length ◽  
Cyclic Spectrum

The direct sequence spread spectrum (DS-SS) signal is a typical kind of LPI signals widely-used in the modern digital communication system, and it is difficult to be detected for its statistical characteristic similar to noise. An algorithm for estimating the code rate, carrier frequency of DS-SS signals was proposed using time-smoothing cyclic periodogram instead of cyclic spectrum according to cyclostationary feature of DS-SS signal to improve the precision of parameter estimation. The estimation performance was analyzed for the cyclic spectrum by time-smoothing cyclic periodogram from the tapering points in the case of limited data length. Simulation results showed that the proposed algorithm is effective.

Downsampling Direct Sequence Spread Spectrum Signal Using Orthogonal Pretreatment

2014 ◽  
Vol 610 ◽  
pp. 944-948
Author(s):  
Jin Bo Zhang ◽  
Jian Cheng ◽  
Lei Yang
Keyword(s):  
Spread Spectrum ◽  
Strong Correlation ◽  
Sampling Rate ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Sensing Matrix ◽  
Pretreatment Method ◽  
Reconstructed Signal ◽  
Nyquist Rate ◽  
Simulation Results

The Direct Sequence Spread Spectrum (DSSS) signal is widely used because of its good concealment and anti-jamming performance. The Compressive Sensing (CS) theory reduced the sampling rate of the DSSS signal effectively compared with the traditional Nyquist-rate sampling theory. While in the process of CS sampling the sensing matrix and the sparse basis generally have a strong correlation when the DSSS signal is decomposed with a complete dictionary. This paper presents a novel orthogonal pretreatment method with which the incoherence between sensing matrix and sparse basis can be improved. As a result, the reconstructed signal is more accurate. Simulation results demonstrate that this method is effective and efficient.

scholarly journals Digital Modulator and Demodulator IC for RFID Tag Employing DSSS and Barker Code

2012 ◽  
Vol 10 (6) ◽  
Author(s):  
M. S. Amin ◽  
M. B. I. Reaz ◽  
J. Jalil ◽  
L. F. Rahman
Keyword(s):  
Radio Frequency Identification ◽  
Spread Spectrum ◽  
Multipath Fading ◽  
Cmos Technology ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Rfid Tag ◽  
Frequency Identification ◽  
Simulation Results ◽  
Barker Code

Radio frequency identification (RFID) is lagging behind because of vendor specific solutions and expensiveimplementation cost. In particular, the reader is the most expensive part. A WiFi compatible tag was proposed to usethe WNIC as an RFID reader. However, no specific modulator or demodulator was suggested. This paper analyzesthe various IEEE 802.11 standards and their modulation and coding techniques keeping the desired properties of anRFID system in consideration. After the analysis, a digital modulator and demodulator for RFID tag in IEEE 802.11protocol employing Direct Sequence Spread-Spectrum (DSSS) and coding is proposed. A MOD-11 synchronouscounter is designed for the 11-bit encoder which generates the desired Barker code. Data are multiplied with thisBarker code to modulate the data, and the received data are multiplied with the Barker code to demodulate them. Theproposed modulator and demodulator are implemented in 0.18μm CMOS technology. The simulation results showthat 1 bit is spread to 11 bits by the modulator and 11-bit received data are demodulated to 1 bit correctly. Theproposed design is simple, resistant to multipath fading and interference and offers the highest distance with thelowest BER for an RFID tag.

Adaptive Algorithm for Anti-Jamming in Broadband Communication

2014 ◽  
Vol 716-717 ◽  
pp. 1252-1256 ◽  
Author(s):  
Jian Hua Cui ◽  
Nai Ping Cheng
Keyword(s):  
Frequency Domain ◽  
Spread Spectrum ◽  
Adaptive Algorithm ◽  
Design Method ◽  
Direct Sequence Spread Spectrum ◽  
Performance Comparison ◽  
Narrowband Interference ◽  
Direct Sequence ◽  
Detailed Design ◽  
Simulation Results

This paper presents a method to suppress narrowband interference in the direct sequence spread spectrum communication based frequency domain adaptive algorithm. The method determines the interference threshold by N-sigma algorithm and calculates the cut-off condition by separating the signal. The method suppresses the narrowband interference by frequency domain batch algorithm. This paper gives a detailed design method and simulation results, and makes a performance comparison with other methods. The results show that, the method in this paper has better performance than other methods. It is suitable for narrowband interference suppression in broadband systems.

Research of Anti-Multipath Interference Capability in Direct Sequence Spread Spectrum Communication System by Simulation

2013 ◽  
Vol 846-847 ◽  
pp. 592-595
Author(s):  
Ping Hua Zhang ◽  
Xiu Liang Huang ◽  
Zhong Yue He
Keyword(s):  
Time Delay ◽  
Fading Channels ◽  
Spread Spectrum ◽  
Communication System ◽  
Rayleigh Fading ◽  
Multipath Fading ◽  
Direct Sequence Spread Spectrum ◽  
Rayleigh Fading Channels ◽  
Direct Sequence ◽  
Simulation Results

The effects of multipath fading with time delay longer or shorter than one chip interval on DSSS system are mathematically and experimentally researched. Simulation results indicate that DSSS system can efficiently overcome multipath fading in multipath Rayleigh Fading channels. And the spreading gain is not the higher the better, it must be chosen reasonably.

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 .

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