Hirofumi Tsuda

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—Signal to Noise Ratio (SNR) is an important index for wireless communications. In CDMA systems, spreading sequences are utilized. This series of papers show the method to derive spreading sequences as the solutions of the non-linear programming: maximize SNR. In this paper, we consider a frequency-selective wide-sense-stationary uncorrelated-scattering(More)
—Recently, the new spreading sequence obtained by the Weyl sequence is proposed for CDMA systems. Its cross-correlation function follows O(1 N), where N is the code length of the spreading sequence. In this paper, we optimize the Weyl sequence code design to assign to each user for CDMA systems and we analytically calculate its theoretical SIR (Signal to(More)
—Signal to Noise Ratio (SNR) is an important index for wireless communications. There are many methods for increasing SNR. In CDMA systems, spreading sequences are used. We consider the frequency-selective wide-sense-stationary uncorrelated-scattering (WSSUS) channel and evaluate the worst case of SNR. We construct the non-linear programing for maximizing(More)
—Signal to Noise Ratio (SNR) is an important index for wireless communications. In CDMA systems, spreading sequences are utilized. This series of papers show the method to derive spreading sequences as the solutions of non-linear programming: maximize SNR. In this paper, we derive the optimization problems with the expression SNR derived in Part I and the(More)
CDMA is communication systems in mobile radio networks. To improve CDMA systems, new spreading sequences have been proposed. To design spreading sequences, it is necessary to increase the SNR. In classical approaches, the denominator of the SNR is not differentiable. We transform the SNR formula with the two types of orthogonal basis vectors. The(More)
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