A simplified aperiodic cross-correlation model for direct-sequence spread-spectrum multiple-access communication systems

Author(s):  
Chi-Kin Chan ◽  
Wong-Hing Lam
Author(s):  
Fawzan Galib Abdul Karim Bawahab ◽  
Elvan Yuniarti ◽  
Edi Kurniawan

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 .


2018 ◽  
Vol 27 (13) ◽  
pp. 1850207
Author(s):  
Said Sadoudi ◽  
Ibrahim Fennouh ◽  
Camel Tanougast

In this paper, we propose a new hyperchaos-based spreading codes generator (HSCG) for multi-users direct sequence spread spectrum (DSSS) communication systems. For experimental validation, we implement the proposed generator in Xilinx FPGA Virtex-5 technology. Contrary to the traditional spreading codes, the proposed HSCG offers interesting statistical properties such as good autocorrelation, very small cross-correlation, no repetition of the generated spreading codes and high degree of security. In addition, the developed hardware architecture used for implementing the HSCG permits to generate simultaneously an infinite number of multi-length spreading codes with high hardware performances in terms of logic area consumption, throughput and latency. Real-time results are given for 32-, 64- and 128-bit chaotic spreading codes. All of these properties are validated and compared with that of classical codes (Gold sequences, Walsh–Hadamard) through bit error rate (BER) performance evaluation in a DS-CDMA system in AWGN and time-invariant multipath channels. With its interesting performances, the proposed HSCG is very useful for the next generations of mobile communication systems.


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