Efficient despreaders for multi-code CDMA systems

It is shown that the implementation efficiency of the despreaders for multi-code CDMA systems directly depends on the efficiency of elementary bank of correlators corresponding to the applied binary spreading sequences, regardless of the spreading and modulation format. Until now two kinds of spreading sequences are proposed for the application in the multicode transmission schemes: sets of Walsh sequences and sets of orthogonal Gold (1967) sequences. The paper presents the efficient implementation of the bank of correlators matched to the set of orthogonal Gold sequences. The method of finding all the permutations which map the orthogonal Gold sequences into the Walsh sequences is also shown.