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Narrow-band interference excision in spread-spectrum systems using new N-sigma algorithm based on fuzzy threshold 被引量:4
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作者 Feng Jining Wu Siliang Wang Ju 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第1期20-26,共7页
The key to narrow-band interference excision in frequency domain is to determine the excision thresh- old in direct-sequence spread-spectrum (DS-SS) systems. The excision threshold is a non-linear function related t... The key to narrow-band interference excision in frequency domain is to determine the excision thresh- old in direct-sequence spread-spectrum (DS-SS) systems. The excision threshold is a non-linear function related to the number and the power of interference, and attempting to get the exact relation of threshold related to the number and the power of interference is almost impossible. The N-sigma algorithm determines the excision threshold using subsection function; however, the excision threshold determined by this method is not exact. A new method to determine the threshold of N-sigma algorithm is proposed. The new method modifies the scale factor N by use of the membership function. The threshold determined by this method is consecutive and smooth, and it is closer to the fact than that of the initial N-sigma algorithm. The GPS signal and single-tone (CW) interference (that is, typical narrow-band interference) are implemented in the simulation, and the results are presented to demonstrate the validity of the new algorithm. 展开更多
关键词 direct-sequence spread-spectrum systems adaptive frequency domain interference suppression fuzzyfunction GPS signal.
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Blind Estimation of Long Code DSSS Signal Based On Subspace Tracking 被引量:1
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作者 Ma Chao Zhang Limin Wang Jianxiong 《International Journal of Technology Management》 2013年第1期80-83,共4页
Aiming at solving the blind estimation problem of dispreading spectrum sequence under low SNR, a spread-spectrum estimation algorithm based subspace tracking is studied in this paper. This method avoids the direct eig... Aiming at solving the blind estimation problem of dispreading spectrum sequence under low SNR, a spread-spectrum estimation algorithm based subspace tracking is studied in this paper. This method avoids the direct eigen decomposition, using the sliding window technique to obtain the code synchronization, then use segmentation subspace tracking method estimate spreading sequence and splice in a certain order to achieve pseudo-code blind estimation. The results show that the algorithm can complete the accurate estimation of PN code sequence in low SNR conditions, reduce the amount of data storage and be easy hardware implementation 展开更多
关键词 dsss blinding estimation of spread-spectrum waveform subspace tracking long code
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Rapid Coherent Acquisition for PN Sequence UsingOptimum Search Algorithm
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作者 宋阳 胡光锐 《Journal of Shanghai University(English Edition)》 CAS 2005年第4期339-343,共5页
An optimun search algorithm for the coherent acquisition in direct-sequence spread-spectrum (DSSS) receivers is proposed and analyzed in this paper. The system consists of two major parts: a phase region estimator ... An optimun search algorithm for the coherent acquisition in direct-sequence spread-spectrum (DSSS) receivers is proposed and analyzed in this paper. The system consists of two major parts: a phase region estimator and a phase alignment detector. We use an auxiliary sequence to correlate the incoming signal in the phase region estimator. Since the cross-correlation value between the auxiliary sequence and the incoming PN signal has linear magnitude, and can provide the direction for the phase updating, an optimum search algorithm, try and error method, can be adopted to obtain the phase region information of the incoming signal. The mean acquisition time is derived through the signal flow graph theory. The time is compared with that of the conventional serial search scheme, and the results show that the proposed scheme can achieve coarse acquisition significantly faster than the conventional scheme. 展开更多
关键词 auxiliary signal direct-sequence spread-spectum(dsss PN sequence try and error synchronization.
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Modeling and Simulation of CDMA Codes in Scilab
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作者 Mouhamed Fadel Diagana Serigne Bira Gueye 《International Journal of Communications, Network and System Sciences》 2015年第7期274-281,共8页
Prior to hardware implementation, simulation is an important step in the study of systems such as Direct Sequence Code Division Multiple Access (DS-CDMA). A useful technique is presented, allowing to model and simulat... Prior to hardware implementation, simulation is an important step in the study of systems such as Direct Sequence Code Division Multiple Access (DS-CDMA). A useful technique is presented, allowing to model and simulate Linear Feedback Shift Register (LFSR) for CDMA. It uses the Scilab package and its modeling tool for dynamical systems Xcos. PN-Generators are designed for the quadrature-phase modulation and the Gold Code Generator for Global Positioning System (GPS). This study gives a great flexibility in the conception of LFSR and the analysis of Maximum Length Sequences (MLS) used by spread spectrum systems. Interesting results have been obtained, which allow the verification of generated sequences and their exploitation by signal processing tools. 展开更多
关键词 Code Division Multiple Access (CDMA) Linear Feedback Shift Register (LFSR) Maximum Length SEQUENCE (MLS) spread-spectrum SCILAB Xcos Direct SEQUENCE Spread Spectrum (dsss)
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