낮은 상호상관관계를 갖는 비선형 이진수열의 생성

Abstract

Spreading sequence is used for spreading spectrum in CDMA. For the purpose of minimizing multiple access interference and expanding the number of the users, it is desirable to use such sequences with low cross-correlation and high linear span. To make the family size larger and the linear span higher, it is inevitable to raise the cross-correlation function value. In the transmission performance and efficiency, an important problem is to find the spectrum and the number of the occurrences of the cross-correlation function values between two different maximal sequences. In this paper, we propose the new maximal sequences which are obtained by the new decimations d= {2^{m-st-1}}/{2^s -1}(2^{n}+2^{st+s+1}-2^{m+st+1}-1 ),d= 2^{m-1}/{2^{s} -1} ( 2^{m (i+1)}-2 ^{mi} +2 ^{s+1}-2^m-1) from some maximal sequences. We will also find the spectrum and the number of the occurrences of the cross-correlation function value from the proposed decimations. Also we propose the new family of the sequences using the decimation which satisfies the condition d =1(mod2^m-1), calculate the cross-correlation spectrum for 0≤t≤2^n−2 and count the number of the whole value occurring for 0≤tau≤2^n-2. For the decimation d=2・2^m-1 we count the number of the cross-correlation function value C_d (tau) =2^m-1 occurring for 0≤t≤2^n−2, for d=2^{m-1} (3·2^{m}-1) we resolve the number of the cross-correlation function value around (). Finally, for the decimation with the condition d==1(mod2^m-1), d==2^k( mod 2^m+1), we analyze the cross-correlation spectrum and the number of the occurrences for tau =Q tau_1, (0 ≤tau_1≤2^m-2). The work on this paper can make it easier to count the number of the occurrence of the cross-correlation function value.