Method and device for orthogonal variable spreading factor codes and hadamard matrices generation

摘要

A method for the generation of variable length orthogonal spreading sequences with maximal length 2k and spreading factor SF or rows of Hadamard matrices of dimension SF, marked by an index n' of k=log2SF bits. In the method the final sequence or row is generated starting from a predefined initial value and repeating partial sub-sequences, as they are or changed in sign depending on the value, 0 or 1 respectively, of each bit of the binary representation of n'. An apparatus for the generation according to the method is composed by an index shift-register (10) in which the index n' is loaded and a sequence shift-register (11) in which the final sequence or row is composed. A transfer circuit (13) takes the partial sequence stored in the sequence shift register (11) inverts it or not depending on the output of the index shift-register and uploads the result in the sequence shift-register appending it to the partial sequence generated up to now. The circuit repeats the loading, eventually the inversion and the storing for each bit of the index in the index shift-register, shifting of one position each time the index shift-register until all the bits of n' have been used.