Device and method for multiuser detection is DS-CDMA system

摘要

Device and method for decorrelated multiuser detection in a DS-CDMA system, is disclosed, which allows real time removal of an MAI(Multiple Access Interference) occurred in the DS-CDMA system, the method including the steps of(a) receiving signals band spread by multiuser spreading codes transmitted from multiuser respectively and despreading the received signals with conjugate complexes of the multiuser spreading codes, to restore each of multiuser messages y, (b) spreading each of the multiuser messages with the multiuser spreading codes, summing, despreading with the conjugate complexes of the multiuser spreading codes, low pass filtering, and subtracting from the multiuser messages y under bit synchronization, for extracting multiple access interference signals Qy according to cross-correlation coefficients between the multiuser spreading codes contained in each of the messages y; for the first time, and (c) adding negative values of the multiple access interference signals Qy extracted in the step (b) to the multiuser messages y under bit synchronization, for restoring each of multiuser messages Z=(I−Q)y having the multiple access interference signals removed therefrom for the first time (where, Q denotes a matrix with its diagonal entries being 0 and the other entries being the cross-correlation coefficients between each of the multiuser spreading codes and I denotes an identity matrix with its diagonal entries being unity, Z=[Z₁, - - - , Z_K] and y=[y₁, - - - , y_K]).