Why spread spectrum?

Dixon, Robert

doi:10.1109/mcomd.1975.1089046

Cited by 18 publications

(7 citation statements)

References 1 publication

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“…If the |R -R′| and N are relatively prime for an odd period N and 2|R -R′| and N are relatively prime for an even period N, the absolute value of the cross-correlation function of these sequences is a constant 1 …”

Section: Resultsmentioning

confidence: 99%

“…Thus, when the period N is an odd number, from Eq. (18), the V N (a) set of R(k) where the absolute value of the difference |R(i) -R(j)| between any two real numbers R(i) and R(j) (i ≠ j) is relatively prime to period N is Thus, based on the conjecture explained in Section 3, when the period N is an odd number, the absolute value of the cross-correlation function of sequences of any two elements is the constant 1 …”

Section: Generating the Orthogonal Periodic Complex Number Sequence Smentioning

confidence: 99%

“…Spread spectrum multiplexing communication systems and electronic watermarking techniques for copyright protection use periodic sequences having small side lobe peaks of the autocorrelation function and a low peak of the cross-correlation function [1][2][3]. M sequences and Gold sequences [2] are used as these sequences, but their crosscorrelation functions are not necessarily small.…”

Section: Introductionmentioning

confidence: 99%

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A generation method of orthogonal periodic complex number sequence sets with lowest peak of cross‐correlation for any period based on chirp sequences

Ohue

2004

Electron Comm Jpn Pt III

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SUMMARYIn this paper, we propose a new generation method of orthogonal periodic complex number sequence sets based on chirp sequences that can derive the orthogonal periodic complex number sequence set having the minimum cross-correlation peak for any period. First, we use the Ohue-Okahisa Conjecture that is proven in a practical range related to the orthogonal periodic polyphase sequence obtained by taking the inverse discrete Fourier transform of a chirp sequence to derive the relationship between the period N having the minimum peak of the cross-correlation and the chirp sequence parameter R, and clearly explain a generation method of an orthogonal periodic complex number sequence pair having the minimum cross-correlation peak for any period. Next, we present a generation method of the orthogonal periodic complex number sequence set having the minimum cross-correlation peak for any two sequences in the set. The dimension of this set is clearly equal to the minimum prime factor of the period N. Furthermore, we present a generation method of the orthogonal periodic polyphase sequence set having the minimum cross-correlation peak for any period and show that the dimension of this set becomes a value 1 less than the minimum prime factor of period N. We show that this generation method can derive the orthogonal periodic complex number sequence set having the minimum cross-correlation peak for periods that could not be generated by conventional techniques and can derive the orthogonal periodic polyphase sequence set demonstrated previously. Finally, we present a generation example of the orthogonal periodic sequence set having the minimum cross-correlation peak and clearly show that the orthogonal periodic complex number sequence set and orthogonal periodic polyphase sequence set having the minimum cross-correlation peak can be generated.

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Section: Resultsmentioning

confidence: 99%

Section: Generating the Orthogonal Periodic Complex Number Sequence Smentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A generation method of orthogonal periodic complex number sequence sets with lowest peak of cross‐correlation for any period based on chirp sequences

Ohue

2004

Electron Comm Jpn Pt III

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“…The system is affected little by interference except in the case of the same code sequence. Since the code sequence has a cryptographic function, confidentiality is high [2]. From the results of field tests, the system is found to be highly compatible with microcellular systems and to have a high frequency use efficiency.…”

Section: Cdma System and Communication Breakingmentioning

confidence: 99%

Communication breaking space for CDMA portable radio telephone

Sugiura

Takakura

Inayoshi

2000

Electron. Comm. Jpn. Pt. I

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“…Spread spectrum was developed in the mid 1950s mainly as a novel form of transmission, overcoming the rigid restrictions in radio bandwidth allocation [3,4]. It is based on the idea of spreading the spectrum of the narrowband message over a much wider frequency spectrum by means of a digital code [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%