| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2012: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Outline of Final Research Achievements |
In this research, we studied a realization of optimum spreading sequences based on nonlinear dynamical systems and a construction of their optimum family. For their applications, we considered asynchronous spread spectrum multiple access communication systems. The main results in the three-year study are summarized as follows. i) Based on the theoretical bounds of the normalized auto- and cross-correlation functions for de Bruijn sequences, we experimentally characterized a good family of de Bruijn sequences in terms of the both normalized auto- and cross-correlation functions. ii) We settled the fundamental problem posed by Fredricksen on existence of the CR sequences in the de Bruijn sequences of length 2 to the n for any odd n. We obtained upper bounds of the total number of distinct auto-correlation functions for the de Bruijn sequences. iii) Using the induced transformations, we obtained sharp upper and lower bounds on the mean value of the stopping time of the interval algorithm.
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