Blind Detection Method of Anti-MAI Based on Wiener Filter

The DS-CDMA system has a serious problem that is the multiple-access interference (MAI). Usually, people use the Multi-User detection (MUD) to cancel the MAI. The Multi-User detection makes the best use of the information of other users to cancel the MAI. Indeedly, MUD can cancel the MAI completely, but it has very large computational burden and it increase the noise of the system, besides, it needs to compute the reversion of the matrix which causes the unstable of the system. The new blind detection method (auxiliary vector filter) of anti-MAI, based on Wiener filter, is studied in this paper. The method needs no more modulation, and no inversion of matrix. Also it can be blindly applied to the forward (base-to-mobile) link and its complexity is very low. The simulation results indicate that the auxiliary vector filter can completely cancel the MAI in DS-CDMA system, and its performance is much better than the matched-filter (MF), the decorrelating filter and the MMSE Multi-User Detection.