Patent ID: 7426528

Claim:
A method for determining a final state, comprising n bits and iterated N times, for a shift register arrangement from a given initial state, comprising n bits, for the shift register arrangement, the iteration rule for the shift register arrangement being given by the characteristic polynomial f ( x )=1 +c 1 ·x+c 2 ·x 2 +. . . +c n−1 ·x n−1 +x n with c 1 , c 2 , . . . , c n−1 ε {0; 1}, where a shift register arrangement state change which corresponds to a number N′ of shift register operations, where 0<N′≦N, is calculated by: a) determining a tap mask which is characteristic of N′ shift register operations; and b) performing n shift register operations, as a result of which the tap mask is used for each shift register operation to obtain one bit from n bits of an N′-fold iterated state of the shift register arrangement, wherein step a) comprises: splitting N′ on the basis of N ′ = ∑ j = 1 k ′ ⁢ ⁢ N i ⁡ ( j ) ; and determining the tap mask which is characteristic of N′ shift register operations using k′ tap masks m i(j) (x), where j=1, . . . , k′, each of the k′ tap masks m i(j) (x) being characteristic of the respective N i(j) shift register operations, wherein the method is used in CDMA transmission systems in order to produce a spreading sequence with an offset of N bits.