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It is well known that the periodic performance of spread spectrum sequence heavily affects the cor-relative and secure characteristics of communication systems.The chaotic binary sequence is paid more and more attention since it is one kind of applicable spread spectrum sequences.However,there are unavoidable short cyclic problems for chaotic binary sequences in finite precision.The chaotic binary sequence generating methods are studied first.Then the short cyclic behavior of the chaotic sequences is analyzed in detail,which are generated by quantification approaches with finite word-length.At the same time,a chaotic similar function is defined for presenting the cyclic characteristics of the sequences.Based on these efforts,an improved method with scrambling control for generating chaotic binary sequences is proposed.To quantitatively describe the improvement of periodic performance of the sequences,an orthogonal estimator is also defined.Some simulating results are provided.From the theoretical deduction and the experimental results,it is concluded that the proposed method can effectively increase the period and raise the complexity of the chaotic sequences to some extent.
It is well known that the periodic performance of spread spectrum sequence heavily affects the cor-relative and secure characteristics of communication systems. The chaotic binary sequence is paid more and more attention since it is one kind of spread spread spectrum sequences. Now, there are unavoidable short cyclic problems for chaotic binary sequences in finite precision. The chaotic binary sequence generating methods are studied first. The short cyclic behavior of the chaotic sequences is analyzed in detail, which are generated by quantification approaches with finite word- length. At the the same time, a chaotic similar function is defined for presenting the cyclic characteristics of the sequences. an improved method with scrambling control for generating chaotic binary sequences is proposed. To quantitatively describe the improvement of periodic performance of the sequences, an orthogonal estimator is also defined.Some simulating results are provided.From the theoretical deduction and the experimental results, it is concluded that the proposed method can effectively increase the period and raise the complexity of the chaotic sequences to some extent.