摘要
带进位反馈移位寄存器序列简称FCSR序列,其中最重要的是极大周期FCSR序列,即l-序列.它有许多类似于m-序列的伪随机性质.令q=p~e,若2为模q的本原元,则以q为联接数的极大周期FCSR序列是l-序列,周期为T=φ(q).
本文首先研究了l-序列在部分周期中(即一个周期内任意连续一段)的0、1分布,给出了估计值,指出当寄存器的级数较大时,其0、1个数大约各占一半.特别的,若联接数为素数p,则l-序列在长为μT(0<μ<1)的任意一段中出现1的个数所占的比例(?)(1)满足:
其次讨论了l-序列的线性复杂度,指出它有紧的上界T/2+1,并给出了一个下界.特别当e≥2时,其线性复杂度有下界2~(t-1)+1+T/p,其中2~t‖(p-1).
FCSR sequences are the abbreviation for feedback with carry shift register sequences. Among these, the most important are maximum-period FCSR sequences, that is, l-sequences. They have many good pseudorandom properties similar to m-sequences. Set q =pe, if 2 is a primitive element modulo q, then the maximum-period sequence generated by a FCSR with connection integer q is an l-sequence, with period T= (q).
In this paper, the distribution of 0 and 1 in a partial period of l-sequences, that is, in a segment shorter than the period, is estimated. It was showed that the 0.'s and 1 's are almost equal when the size of the register is large enough. In particular, if the connection integer is a prime number p, then the proportion of 1's in a segment of l-sequence with length T(0< <1) satisfies
Next the linear complexity of l-sequences is discussed. A tight upper bound (772 + 1) and a lower bound are presented. It is showed that if e 2, then the linear complexity of the l-sequence
is at least 2t-1 +l + T/p, where 2t|| (p-1).
引文
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[1] Partial Period Distribution of FCSR Sequences, IEEE Trans. on Information Theory, vol.49, March 2003, pp. 761-765.
[2] On the Linear Complexity of FCSR Sequences, Applied mathematics-A journal of Chinese universities,已被录用。