1994 Fiscal Year Final Research Report Summary
Comparison among methods for evaluating complexity of pseudonoise seyuences with applications to spread spectrum communicatraes and stream ciphert.
| Project/Area Number |
05650356
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
情報通信工学
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
IMAMURA Kyoki Kyushu Institute of Technology, Professor, 情報工学部, 教授 (60037950)
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| Co-Investigator(Kenkyū-buntansha) |
UEHARA Satoshi Kyushu Institute of Technology, Assistant, 情報工学部, 助手 (90213389)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Pseudonoise sequence / Periodic sequence / Linear Complexity / Maximam Order Complexity / One-symbol substitution / One-symbol insertion / One-symbol deletion / 周期系列 |
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| Research Abstract |
Psudonoise sequences with large complexity, where complexity means the difficulty in identifying the sequence from its partial information, are essential in spread spectrum communications and stream ciphers. The linear complexity (LC) has been used as a convenient measure. In this reasearch we make a comparison among methods for evaluating complexity of sequences over a finite field from such a point of view as a small change of a sequence must result in a small change of complexity if the complexity is a suitable one. Our main results are
1.Unstable behaviors of LC are made clear for three kinds of minimum changes (one-symbol substitution, one-symbol insertion or one-symbol deletion per one period) of periodic sequences.
2.It is shown that in case of m-sequences extreme improvements can be made by using maximum order complexity (MOC) instead of LC,where MOC is a generalization of LC to the case of nonlinear difference relation.
Further research is desirable on the following problems.
1.to find theoretical methods for evaluating MOC and to generalize the results on m-sequences to other sequences.
2.to make similar descussions for sequences over a finite ring.
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Research Products
(9 results)
