Search of long biphase sequences for pulse compression using fractal dimension
Kan Araki, Akito Miyoshi · Electronics and Communications in Japan (Part I Communications) · 2004
Abstract In this paper, we propose a search technique for low sidelobe, long biphase sequences that uses the fractal dimension and reduces the computational complexity. We selected the Legendre Sequence (LS) code having a compression ratio that can be relatively freely selected and can be easily implemented in hardware as the original code sequence, which becomes the starting point of the search. With the fractal dimension of a sign run of this sign sequence as the observed parameter of the decrease in the sidelobe in pulse compression, the first step is to invert each sign and search for an improvement in the sidelobe level. Furthermore, the sign inversion position is limited and the search computational complexity is drastically reduced by the sign decision of a change in the fractal dimension and the statistical distribution of the sign inversion position and the fractal dimension. By using this technique and selectively sorting the original LS code that is 1000 to 2500 signs long, an SLL improvement (maximum 1.3 dB) was seen for some codes, and the effect on existing LS codes was quantitatively verified. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(11): 87–98, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecja.10175