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On the distinctness of binary sequences derived from $2$-adic expansion of m-sequences over finite prime fields

Information Theory 2014-02-20 v1 math.IT

Abstract

Let pp be an odd prime with 22-adic expansion i=0kpi2i\sum_{i=0}^kp_i\cdot2^i. For a sequence a=(a(t))t0\underline{a}=(a(t))_{t\ge 0} over Fp\mathbb{F}_{p}, each a(t)a(t) belongs to {0,1,,p1}\{0,1,\ldots, p-1\} and has a unique 22-adic expansion a(t)=a0(t)+a1(t)2++ak(t)2k,a(t)=a_0(t)+a_1(t)\cdot 2+\cdots+a_{k}(t)\cdot2^k, with ai(t){0,1}a_i(t)\in\{0, 1\}. Let ai\underline{a_i} denote the binary sequence (ai(t))t0(a_i(t))_{t\ge 0} for 0ik0\le i\le k. Assume i0i_0 is the smallest index ii such that pi=0p_{i}=0 and a\underline{a} and b\underline{b} are two different m-sequences generated by a same primitive characteristic polynomial over Fp\mathbb{F}_p. We prove that for ii0i\neq i_0 and 0ik0\le i\le k, ai=bi\underline{a_i}=\underline{b_i} if and only if a=b\underline{a}=\underline{b}, and for i=i0i=i_0, ai0=bi0\underline{a_{i_0}}=\underline{b_{i_0}} if and only if a=b\underline{a}=\underline{b} or a=b\underline{a}=-\underline{b}. Then the period of ai\underline{a_i} is equal to the period of a\underline{a} if ii0i\ne i_0 and half of the period of a\underline{a} if i=i0i=i_0. We also discuss a possible application of the binary sequences ai\underline{a_i}.

Keywords

Cite

@article{arxiv.1402.4590,
  title  = {On the distinctness of binary sequences derived from $2$-adic expansion of m-sequences over finite prime fields},
  author = {Yupeng Jiang and DongDai Lin},
  journal= {arXiv preprint arXiv:1402.4590},
  year   = {2014}
}

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7 pages