Cdma Blind Multiuser Detection Technique Applied Research

The advantages of DS/CDMA communication system are increased capacity,soft capacity,soft handover,higher spectral efficiency and the ability to resist the effects of multi-path fading, and so on. However, the MAI and near-far problems in DS/CDMA limit the further application of the technique.Now, DS/CDMA communication system mostly adopts power-control technique to deal with MAI problem. The technique only mitigate MAI. The third generation mobile communication system regards multiuser detection as an effective method to overcome MAI.Most of the researches focus on the blind multiuser detector, because it has no needs of training sequence and the apriori knowledge of interferential users, and it has the merits of higher efficiency,lower complexity of the implementation, and so on. First, the performance of the conventional single-user detector(CD),the optimal multiuser detector(OMUD),the decorrelating detector(DD) and MMSE blind multiuser detectors have been analyzed in this paper, via simulation confirmation, an effective blind multiuser detector that can solve MAI and near-far problem is attained, its implementation is introduced preparatorily in this paper. Secondly, a method combining WCDMA criterion that solve multi-path fading problem is proposed.Lastly, computer simulation analyse and compare show that the modified blind multiuser detector with fast convergence has excellent capabilities to resist MAI,near-far effect and the effects of multi-path fading.